Read the most frequently asked 100 top Mechanical Engineering multiple choice questions and answers PDF for freshers and experienced. Mechanical Engineering objective questions and answers pdf download free..
Mechanical Engineering Multiple Choice Questions and Answers PDF Experienced Freshers
1. How many years did it take for you to complete school?
Express your details like this.
I did it in 4 years for undergraduate (summers included) and 2 more for Masters Degree, part time.
2. What was the hardest class in Engineering you had to take?
Engineering Circuit Analysis. I don't do well with that stuff.
3. Did you have a favorite project that you had to do while in school?
I worked on a ground coupled heat pump project that I really liked. Very interesting stuff, and environmentally worth it.
4. Where do you work in Engineering company?
Presently, I work for an Engineering company designing a solar-sourced power plant. I am building a computer model of it. Pretty neat, huh?
5. What are some of the projects you are currently working on in Engineering?
Besides the computer model, I have been working on some pump selection/purchases, and some system designs.
6. Is there a high demand for mechanical engineers right now?
I would say that there is, because the economy is up and companies are spending more money.
7. How many mechanical engineers work with you at your place of employment?
There must be about 20 or so? Not sure.
8. What are your specific job requirements in mechanical engineers?
Not sure I understand your question. I need skills in Thermodynamics, and computer modeling, as well as some heat transfer and fluid dynamics. I am pretty broad skilled.
9. What is the average salary rate in mechanical engineering job?
Depending on where in the country you work, I earn around $80,000 permanent employment, or $100,000 contract.
10. Does the rate increase by experience or number of years worked?
absolutely Yes to both.
11. Do you receive good benefits as an engineer job?
Depending on the company, Yes. Being an engineer is a good choice. If it is money you want, be a MD. That pays more.
12. What was the hardest part of obtaining your engineering degree?
Finishing my Masters degree. I did it later in life, and shouldn't have waited. Advanced math was difficult for me, as was, as I said, anything electrical. (Now I work for electric utilities in power plants. ... Go Figure! lol
13. Do you work for many hours each day?
Usually 8 hour days, but lately I have been working 10 hour days.
14. What school did you attend in engineering?
I attended the University of _________. A small school, Good education, low cost. Not any scenery to distract you either.
15. When did you decide to become and mechanical engineer and why?
Good question. I decided to become a Mechanical Engineer during my first semester. It just seemed to fit the things I enjoyed.
16. What is the most important thing you have achieved as an engineer?
I wrote some subroutines that are used in a popular software today. Lots of fun, but it didn't pay much.
17. What is the most important, or helpful,project that you have contributed to?
I hope this one. The solar-sourced power plant.
Its up to you to show what is your the most important and helpful project...
18. What is a feasibility study?
In order to make wise investments in a marketplace experiencing increasing levels of risk, companies are turning to feasibility studies to determine if they should offer new products, services or undertake a new business endeavor. The purpose of a feasibility study is to determine if a business opportunity is possible, practical, and viable. When faced with a business opportunity, many optimistic people tend to focus on just the positive aspects.
A feasibility study enables a realistic view at both the positive and negative aspects of the opportunity. A feasibility study is an important tool for making the right decisions. A wrong decision often leads to business failure. For example, only 50% of start-ups are still in business after 18 months and only 20% are in business after 5 years.
19. Is it possible for something to explode in space like in the movies?
Yes, provided there is an oxygen source. A spaceship with liquid hydrogen and liquid oxygen will blow up quite well in the vacuum of space. Chemical explosives will also explode in space since they function by breaking weakly bonded chemical components; no oxygen is necessary. Nuclear explosions can of course occur in space, too. The United States military in the 60's performed a series of nuke tests in outer space, and found out what EMP can do, when they briefly wiped out Hawaii's electrical grid for a few hours.
20. What are the minerals needed to make or build a car?
a) Sulfur is used in tire construction
b) Aluminum and iron in the car body and engine
c) Quartz is used in windshield construction
d) Chromium is used for chrome plating
e) Copper is used in wiring
f) Magnesium may be used in the wheels
g) Zinc would be used in rust plating
h) Gold may be used in the spark plugs and in electrical connections
i) Tin may be used in solder
j) Lead will be used in the batteries
k) Tungsten may be used in the light bulb filaments
21. How do you determine what suction pressure should be in R22 air conditioning compressors suction line?
The type of refrigerant used and sometimes the amount of charge determines the proper suction pressure of any air conditioning or refrigeration system.
22. How do motion detectors work?
Motion detectors work to help with construction work.
23. If the black box flight recorder is never damaged during a plane crash, why not the whole airplane made out of that stuff?
The SR-71 was made mostly out of Titanium (very high strength to weight ratio) and it got off the ground fine. In addition, a two-seat airplane cost $33 million in 1960s dollars, so no one would ever be able to afford an airliner made out of it.
24. How do you repair a hydraulic jack?
In general, it seems simple: polishing scored cylinders and pistons, replacing worn seals, replacing excessively worn or damaged parts, etc. However, for an ordinary person, the problem I have run into is finding a readily accessible source of parts, as the hydraulic repair industry seems to be a closed fraternity.
25. Does the position of a chicken egg affect the amount of weight it can withstand?
Yes. Lying on its side, it will break with very little pressure. That is why, when you break an egg, you always strike the side.
26. Where do you put the oil in a compressor?
In the reciprocating compressors, you fill the crankcase with the lubricante.
In screw compressors, there is a reservoir to separate oil from compressed air, that reservoir works as the oil sump of the screw compressor.
27. What is a pneumatic system?
Pneumatic system is a system that uses air to power something. For instance, have you seen the tube systems at bank drive-up tellers? Air is used to push the tubes back and forth from the teller to the customer.
Air is also used to power drills, sanders, grinders, and the like at garages and car body shops.
28. What kinds of pipes are used for steam lines?
Normally galvanized pipes are not used for steam. Mild steel with screwed or welded fittings are the norm. Pressure and temperature are very important factors to be considered in what type of materials to be used. Steam even at low pressures can be extremely dangerous.
29. What is the difference between shear center flexural center of twist and elastic center?
The shear center is the centroid of a cross-section. The flexural center is the center of twist, which is the point on a beam that you can add a load without torsion. The elastic center is located at the center of gravity. If the object is homogeneous and symmetrical in both directions of the cross-section then they are all equivalent.
30. What is ferrite?
Magnetic iron rock
31. What is the difference between projectile motion and a rocket motion?
A projectile has no motor/rocket on it, so all of its momentum is given to it as it is launched. An example of a projectile would be pen that you throw across a room.
A rocket or missile does have a motor/rocket on it so it can accelerate itself while moving and so resist other forces such as gravity.
32. Is shear thinning fluids and the linear viscoelastic fluids are the same?
No
33. What is the difference between the flight of a plane and a helicopter?
Both use the pressure difference caused by air moving over the wings at different speeds to generate lift a plane by moving those wings in the direction of travel, a helicopter by spinning the "wings" around at high speed.
34. What is jet plane?
An aircraft powered by a jet engine.
35. How does length and initial angle affect the period in a simple pendulum?
The longer the pendulum is the greater the period of each swing. If you increase the length four times, you will double the period.
It is hard to notice, but the period of a pendulum does depend on the angle of oscillation. For small angles, the period is constant and depends only on the length of the pendulum. As the angle of oscillation (amplitude) is increased, additional factors of a Taylor approximation become important. (T=2*pi*sqrt (L/g) [1+theta^2/16+...] and the period increases.
Interestingly, if the pendulum is supported by a very light wire then the mass of the object at the end of the pendulum does not affect the period. Obviously, the greater the mass, the less any air friction, or friction at the pivot will slow the pendulum. Also interestingly, the pendulum period is dependant on the force of gravity on the object (g). One must not assume that g is constant for all places on Earth.
36. How does a Coal Power station produce electricity?
A fossil fuel power plant (FFPP) (also known as steam electric power plant in the US, thermal power plant in Asia, or power station in the UK) is an energy conversion center designed on a large scale for continuous operation. Just as a battery converts relatively small amounts of chemical energy into electricity for temporary or intermittent use, the FFPP converts the energy stored in fossil fuels such as coal, oil, or natural gas successively into thermal energy, mechanical energy, and finally electric energy for continuous use and distribution across a wide geographic area.
Usually, the coal is utilized to convert water into steam in boilers (thermal energy). The steam is then used to drive steam turbines (mechanical energy). The turbine shaft is coupled to a generator shaft, which generates electricity.
37. What is a cotter joint?
These types of joints are used to connect two rods, which are under compressive or tensile stress. The ends of the rods are in the manner of a socket and shaft that fit together and the cotter is driven into a slot that is common to both pieces drawing them tightly together. The tensile strength of the steel is proportionate to the strength needed to offset the stress on the material divided by the number of joints employed.
38. What are the thermal conductivity properties of brass?
109 W/ (m*K) @ 300K
39. What is the gas constant R for air?
Air gas constant is Rair=R/28.97=0.2869 (J/g K) = 286.9 (J/kg K)
40. What is the alloy of tin and lead?
A tin and lead alloy is commonly called solder. Usually solder is a wire with a rosin core used for soldering. The rosin core acts as a flux.
41. What does F.O.F. stand for in piping design?
FOF stands for Face of Flange. A flange has either of the two types of faces:
a) Raised face
b) Flat face
The F.O.F is used to know the accurate dimension of the flange in order to avoid the minute errors in measurement in case of vertical or horizontal pipelines.
42. Why is the suction pipe of vapor compression and refrigeration system insulated?
The vapor compression and refrigeration system is used to minimize sweating of the air around the pipe. When the air is exposed to a cool surface, its water vapor condenses.
43. What is the full form of WCB in ASTM?
American Society for Testing and Matreails
44. What is the main purpose of an airspeed indicator in an aircraft?
The primary purpose of an airspeed indicator in an aircraft is to give the pilot some sense of how fast the aircraft is moving. A pitot tube, which is a forward pointing hollow tube that is mounted on the plane, is pressurized by the force of the air the plane encounters as it flies. This air pressure is compared to a static reference, and the difference is proportional to the airspeed. The faster the plane moves, the higher the pressure in the Pitot tube, and the greater the difference between that and the reference. All that will result in higher indicated air speed. There are some issues associated with the accuracy of the system (like when the plane is flying into a headwind), and information on. The pictures are informative, and a reader can pick up a handful of specialized terms relating to the device and the principles upon which it operates.
45. What is a uniformly distributed load?
A UDL or uniformly distributed load is a load, which is spread over a beam in such a way that each unit length is laded to the same extent.
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46. What are the differences between pneumatics and hydraulics?
a) Working fluid: Pneumatics use air, Hydraulics use Oil
b) Power: Pneumatic power less than hydraulic power
c) Size: P components are smaller than H components
d) Leakage: Leaks in hydraulics cause fluid to be sticking around the components. In pneumatics, air is leaked into the atmosphere.
e) Pneumatics obtain power from an air compressor while hydraulics require a pump
f) Air is compressible, hydraulic oil is not
47. What is enthalpy?
Enthalpy is the heat content of a chemical system.
48. What is a positive displacement pump?
A positive displacement pump causes a liquid or gas to move by trapping a fixed amount of fluid or gas and then forcing (displacing) that trapped volume into the discharge pipe. Positive displacement pumps can be further classified as either rotary-type (for example the rotary vane) or lobe pumps similar to oil pumps used in car engines. These pumps give a non-pulsating output or displacement unlike the reciprocating pumps. Hence, they are called positive displacement pumps.
49. Why would you use hydraulics rather than pneumatics?
Hydraulics is suitable for higher forces & precise motion than pneumatics. This is because hydraulic systems generally run at significantly higher pressures than pneumatics systems. Movements are more precise (repeatable) because hydraulics uses an incompressible liquid to transfer power whilst pneumatics uses gases.
Pneumatic systems have some advantages too. They are usually significantly cheaper than hydraulic systems, can move faster (gas much less viscous than oil) and do not leak oil if they develop a leak.
50. What is the formula for Heat loss in a pipe?
Pipes are generally cylindrical in structure of amount of heat loss through pipe is given by the formula
Q= 2 pi k L (T1-T2)/ln (r2/r1)
Where
k=conductivity of material of which pipe is made
T1= temperature of inside layer pipe
T2=temperature outside layer of pipe
L= length of pipe
r1= inner radius
r2=outer radius
ln=natural logarithm
pi=22/7
The above condition applies for steady state flow, single layer over cylinder and neglecting conductivity
To take conductivity into account term Qmust be added
Q*=2 pi L {r1 hi (Ti-T1) +r2 ho (T2-To)}
hi=convective coefficient for inside layer
ho=convective coefficient for outside layer
Ti= temperature of inside space of pipe
To=temperature of outside space of pipe
51. What was the spinning jenny?
The spinning jenny is a multi-spool spinning wheel. It was invented circa 1764 by James Hargreaves in Stanhill, near Blackburn, Lancashire in the north west of England (although Thomas Highs is another candidate identified as the inventor).
52. Who invented the four-stroke engine?
Nikolavs August Otto, German
53. What is meant by payload for aircraft?
The payload is the cargo that it carries.
54. Who invented springs?
Rewat
55. How fast is a jet plane?
Fighter jet aircraft fly at speeds in the low mach numbers. Mach 1 is roughly 750 miles per hour, give or take, and military jets can fly at well over a thousand miles per hour. Back in the day (July of 1976), the SR-71 set the jet speed record. Radar clocked the thing at 2242 mph. Oh, and the record still stands. This highly sensitive aircraft project probably holds back data that would top this figure, but the information will not be coming out soon if it exists. The Blackbird is the answer to your prayers. As a caveat, there is a much faster jet called a scramjet, but it is unmanned. The NASA X-43A can hit Mach 9.6, which is about 7300 miles per hour.
56. What are the uses of windmill?
Windmills were traditionally used for processing grains, later they started to be used for electricity production as well. Windmills can also be used to pump water.
57. What is isometric drawing?
It is a 3-D drawing used by draftsmen, architects etc
58. How does iron ore turn into steel?
To make Steel, Iron Ore is refined into iron and all the carbon is burned away using very high heat (Bessemer). A percentage of Carbon (and other trace elements) are added back to make steel.
59. What is the world is hardest metal?
Rhenium diboribe
60. What is a machine shop?
A facility that uses machines to fabricate devices from stock raw materials or to modify mechanisms based upon provided specifications. Also, know as "Back" Shops.
The common machines in a machine shop are a lathe, a drilling m/c, a miller, a shaper/planer, grinding machine and so on.
1. What are the advantages of gear drive?
In general, gear drive is useful for power transmission between two shafts, which are near to each other (at most at 1m distance). In addition, it has maximum efficiency while transmitting power. It is durable compare to other such as belts chain drives etc. You can change the power to speed ratio.
Advantages: -
It is used to get various speeds in different load conditions.
It increases fuel efficiency.
Increases engine efficiency.
Need less power input when operated manually.
62. Why is thick steel wire stronger than thin steel wire?
The material will yield when stress reaches a critical value.
Stress = Load / Area
Thick steel wire is stronger than thin steel wire because there is more cross sectional area in the thick wire. Although the material's strength in load per unit area would be the same, the ultimate load that the wire can sustain would be more in the thick wire.
A simple way of looking at it is to imagine a thick wire as a number of thin wires stuck together. If a thin wire can support a mass of 1kg then 2 thin wires can support 2kg. A wire which is twice as thick (twice the cross sectional area) can also support 2kg.
63. What is the coefficient expansion of transformer oil?
Transformers can be filled with various types of Refined Mineral Oil. That coefficient is something you would find in specifications of the supplier.
64. What is a clock maker called?
A watchmaker or clockmaker is called a horologist.
65. What are the types of sensors and their explanation?
There are many types of sensors. They are used to measure and/or detect a huge variety of conditions including temperature, pressure, level, humidity, speed, motion, distance, light, or the presence/absence of an object and many other types.
Sensors in some cases react to the environment in which they are placed and this reaction is used to measure the property being sensed. For example, a common temperature detector is known as an RTD (resistance temperature detector) and this contains a platinum wire. The electrical resistance of the wire changes with temperature so how the resistance changes can be used to measure the temperature.
Many sensors use this type of principle where the variation of an electrical property of a sensing element is a measure of a property being sensed.
Other types of sensors emit a signal and either measure how the area reacts to the emission or measure the reflection of the signal bouncing off an object in front. Inductive proximity sensors are one of the commonest sensors in use today. They emit a small electromagnetic field and use this to sense the properties of the area in front of the sensor.
66. What is 1810 stainless steel?
1810 Stainless Steel is the European grade that is equivalent to AISI 304 Stainless Steel. It is the most common stainless steel going. Here is the rundown:
Fe, <0.08% C, 17.5-20% Cr, 8-11% Ni, <2% Mn, <1% Si, <0.045% P, <0.03% S
67. How is natural gas better than LPG?
Without getting into the chemistry and physics of the two different types of gases, natural gas has a higher but output than liquid propane gas. In other words, higher the available energy output/more energy is efficient.
68. How can heat be applied to acrylic?
In most hardware stores, you can find what has called a Heat Gun. Hold the heat gun about 6inches away from the acrylic you intend on bending say the bumper on a car. They are plastic these days, but will melt when you apply heat to them. Using a cold scraper, you can usually mold two pieces back together using the heat gun.
69. Did Elevation affect weight?
The acceleration of Gravity is less, as you get further away from the center of the earth. This would cause you to weigh less. The equation for the force of gravity is GMm/(R^2). Where G is the universal Gravity Constant which is something like 6.67x10^ (-11) and M is the mass of the earth, and m is the mass of the weight being measured. R is the distance from the center of the earth that increases as you increase in altitude.
70. Which conducts heat faster steel copper or brass?
Copper conducts heat faster than steel or brass. Any material that is good for conducting heat is also good for electricity in most cases. Wood terrible for transferring heat thus is also insulator for electric.
71. What is the Device that converts sound energy into mechanical energy?
Sound energy is mechanical energy. No devices are required to make a conversion.
72. What is a mechanism?
A mechanism is a system of moving parts that changes an input motion and force into a desired output motion and force.
73. Accelerometers measure acceleration. How do you measure the moment of inertia?
You calculate it using your moment of inertia equations corresponding to the geometry of the object. There is no simple device I do not think that you can buy to just measure it.
74. Who built the first rocket that Robert Goddard invented?
Goddard built his own early rockets.
75. What is a slined joint?
Cotter Pin
76. How pipe flanges are electrically insulated?
Pipe flanges are protected from corrosion by means of electrolysis, with dielectric flanges. The piping system is electrically insulated by what is called a sacrificial anode. A bag of readily corrodible metal is buried in the ground with a wire running from the pipe to the bag so that the sacrificial anode will corrode first. If any electrical current charges the pipe, it also serves as a ground.
77. Why would some industries select pneumatics over hydraulic?
Actually, there is need for air reservoir in industrial pneumatics systems. Hydraulics can handle more powerful applications than pneumatics for the same overall dimensions, or can be more compact for the same power.
78. What is a Process Flow Diagram?
A Process Flow Diagram (or System Flow Diagram) shows the relationships between the major components in the system. It also has basic information concerning the material balance for the process.
79. How do you convert 95 feet into square feet?
You cannot convert feet into square feet; they are two entirely different and incompatible units. Converting feet to square feet is like converting apples to oranges.
A linear foot is a unit of distance. A square foot is a unit of area. If you have a rectangular surface, you can compute the area in square feet by multiplying the length in feet by the width in feet. For example, a rectangular patio that is 12 feet wide by 15 feet long has an area of 12 x 15 = 180 square feet.
80. What is difference between mill and mill-drill?
Today many manufactures are combining machines; a mill/drill is one of these. It is a combination of a drill and a mill, a mill removes stock from material (usually metal, but not limited just to metal, it depends on your application), you use fluted cutters such-as end mills. The drill aspect of the machine is just that it drills holes, with the proper speed for the right size drill.
81. Where pneumatic system is used?
Any system needs redundancy in work needs pneumatics, because the compressor of the pneumatic system has periodical operations (intermittent work, not as hydraulic pump). The compressed air could be accumulated in tanks with high pressures and used even if the compressor failed.
82. What is brain of the computer?
The processor (or CPU) is the brain of the computer. This is the part, which does all the "thinking", i.e. maths.
There is no information stored in the CPU, the information is held in the hard disk, and is fished out, acted on by the CPU, and so on.
83. What is a vee used for on the Vee Block?
It holds round/cylindrical material. It is usually used to judge the cylindricity of the cylindrical material.
Normally 90 degrees vee can be used for the marking of the cylindrical cross section surface, level checking.
84. How many litres did 1 cubic meter contains?
1000 litre in a cubic meter
85. What is the weight of 1m3 of seawater?
1 m^3 = 1000 lits
And 1 lit = 1 kg (approx)
Therefore 1 m^3 = 1000 kg (approx)
86. In 1983 what changed about the length of the meter?
The French were the first to define the length of a meter by using an alluminium/platinum alloy bar of a meter length at 25 degrees Celsius. This however is very inaccurate for quantum measurements, as the length of the bar would change two much depending on how you hold it. A better measurement found in 1983 is the distance that light travels in a vacuum in 1/229,792,458ths of a second. (For those of us with a decent knowledge of relativity that measurement is taken in the rest frame). Crazy I know but at least this way any body in a good physics lab can reproduce this distance without the use of some silly French rod.
87. What are the advantages of powder metallurgy?
Power metallurgy is much faster production while holding closer sizes.
88. What are examples of a first class lever?
Examples of some first class levers are scissor, seesaw, hammer, and wrench.
89. How does a boat measure speed?
Knots one nautical mile per hour there are 1 1/8 of a nautical mile in a statute mile
Originally measured by throwing a piece of wood attached to a piece of rope over the back of a boat and counting how many knots went past in a given time.
These days it is more normally measured by:
a) Using a pitot static tube which measure difference in pressure and uses Bernoulli’s equation to find the velocity.
b) Some form of propeller (technically impeller) which is suspended under the boat. The passing water turns, the speed of rotation is measured, and this gives you the speed of the boat.
c) Using ultrasonic to measure the speed, that small bubbles of air in the water passing under the boat go past.
90. What is a steam turbine diaphragm?
Steam turbine comprises of stages, number and size of the stages depends upon the break horsepower of the turbine.
The stage has set of moving and fixed blades. The moving blades are attached to the rotor while the stationary blades are called Diaphragm.
The diaphragm guides the steam to glide over the moving blades for producing rotary motion.
91. What is wrap-around?
The main purpose of a wrap-a-round is to make a straight line around a pipe to aid in cutting the pipe to its proper length. It is used mostly as a template or a straight edge.
92. What instrument in a car measures its speed?
The speedometer and speedometer cable tells the driver how fast the vehicle is going.
What has called a Hall-Effect sensor is used. It uses the principle of magnetic inductance. When a magnetic flux passes through coils of wire, voltage is generated. To use this effect, a magnet is placed in the cars differential. The sensor then can tell when the magnet comes around by a spike in voltage. Since there is a constant amount the car moves with each differential rotation, and with the time between voltage spikes, you can easily divide to get the speed.
This is why changing your cars tires will affect your speedometer. Your car assumes that car moves a certain amount with each differential rotation. If you have larger tires on, then each differential rotation (and axle rotation) your car moves further, and you will move faster than indicated.
93. Can an airplane fly without a tail?
There are a number of aircraft, which are designed without tail assemblies. As for aircraft designed with a tail assembly that may lose it in flight, that's problematic for the flight crew, but there have been instances of portions of tail assemblies being lost due to structural failure or accident that have managed to successfully land.
94. Will going from a 3 tap to a 6 tap increase water pressure?
No, the pressure will be the same, you will get more volume only if your pumps can handle the gpm, to increase pressure you may need a booster pump or a single pump that is rated for your needs.
95. Why gas containers are mostly cylindrical in shape?
The most efficient shape for withstanding high pressure is a sphere but that would be costly to manufacture. A cylinder with a domed top and a domed bottom (look underneath, the flat base is actually welded around the outside, the bottom of the gas container is actually domed) is a much cheaper shape to manufacture whilst still having good strength to resist the internal gas pressure.
96. When was the first space rocket built?
1890
97. How does a hammer mill work?
Big hammers (not the kind you pound nails with) spin out with centrifugal force and beat whatever it is you are grinding into smaller pieces.
98. What are some mechanical laboratory apparatuses?
Welding machine
99. How does a modern submarine move?
Modern submarines move by using some motor to drive a propeller (called a screw). The big u-boats have nuclear reactors that heat water to make steam and have steam turbines that drive the screw through a big reduction gear. Many smaller submarines use a battery bank and electric motors with little propellers on them to move.
100. Is a diesel engines maximum rpm limited by the diesel burn rate?
Yes. In practice however, the maximum rpm is usually limited by the construction of the rotating assembly and the high-pressure injection parts.
Mechanical Engineering Multiple Choice Questions and Answers PDF Experienced Freshers
Express your details like this.
I did it in 4 years for undergraduate (summers included) and 2 more for Masters Degree, part time.
2. What was the hardest class in Engineering you had to take?
Engineering Circuit Analysis. I don't do well with that stuff.
3. Did you have a favorite project that you had to do while in school?
I worked on a ground coupled heat pump project that I really liked. Very interesting stuff, and environmentally worth it.
4. Where do you work in Engineering company?
Presently, I work for an Engineering company designing a solar-sourced power plant. I am building a computer model of it. Pretty neat, huh?
5. What are some of the projects you are currently working on in Engineering?
Besides the computer model, I have been working on some pump selection/purchases, and some system designs.
6. Is there a high demand for mechanical engineers right now?
I would say that there is, because the economy is up and companies are spending more money.
7. How many mechanical engineers work with you at your place of employment?
There must be about 20 or so? Not sure.
8. What are your specific job requirements in mechanical engineers?
Not sure I understand your question. I need skills in Thermodynamics, and computer modeling, as well as some heat transfer and fluid dynamics. I am pretty broad skilled.
9. What is the average salary rate in mechanical engineering job?
Depending on where in the country you work, I earn around $80,000 permanent employment, or $100,000 contract.
10. Does the rate increase by experience or number of years worked?
absolutely Yes to both.
11. Do you receive good benefits as an engineer job?
Depending on the company, Yes. Being an engineer is a good choice. If it is money you want, be a MD. That pays more.
12. What was the hardest part of obtaining your engineering degree?
Finishing my Masters degree. I did it later in life, and shouldn't have waited. Advanced math was difficult for me, as was, as I said, anything electrical. (Now I work for electric utilities in power plants. ... Go Figure! lol
13. Do you work for many hours each day?
Usually 8 hour days, but lately I have been working 10 hour days.
14. What school did you attend in engineering?
I attended the University of _________. A small school, Good education, low cost. Not any scenery to distract you either.
15. When did you decide to become and mechanical engineer and why?
Good question. I decided to become a Mechanical Engineer during my first semester. It just seemed to fit the things I enjoyed.
16. What is the most important thing you have achieved as an engineer?
I wrote some subroutines that are used in a popular software today. Lots of fun, but it didn't pay much.
17. What is the most important, or helpful,project that you have contributed to?
I hope this one. The solar-sourced power plant.
Its up to you to show what is your the most important and helpful project...
18. What is a feasibility study?
In order to make wise investments in a marketplace experiencing increasing levels of risk, companies are turning to feasibility studies to determine if they should offer new products, services or undertake a new business endeavor. The purpose of a feasibility study is to determine if a business opportunity is possible, practical, and viable. When faced with a business opportunity, many optimistic people tend to focus on just the positive aspects.
A feasibility study enables a realistic view at both the positive and negative aspects of the opportunity. A feasibility study is an important tool for making the right decisions. A wrong decision often leads to business failure. For example, only 50% of start-ups are still in business after 18 months and only 20% are in business after 5 years.
19. Is it possible for something to explode in space like in the movies?
Yes, provided there is an oxygen source. A spaceship with liquid hydrogen and liquid oxygen will blow up quite well in the vacuum of space. Chemical explosives will also explode in space since they function by breaking weakly bonded chemical components; no oxygen is necessary. Nuclear explosions can of course occur in space, too. The United States military in the 60's performed a series of nuke tests in outer space, and found out what EMP can do, when they briefly wiped out Hawaii's electrical grid for a few hours.
20. What are the minerals needed to make or build a car?
a) Sulfur is used in tire construction
b) Aluminum and iron in the car body and engine
c) Quartz is used in windshield construction
d) Chromium is used for chrome plating
e) Copper is used in wiring
f) Magnesium may be used in the wheels
g) Zinc would be used in rust plating
h) Gold may be used in the spark plugs and in electrical connections
i) Tin may be used in solder
j) Lead will be used in the batteries
k) Tungsten may be used in the light bulb filaments
21. How do you determine what suction pressure should be in R22 air conditioning compressors suction line?
The type of refrigerant used and sometimes the amount of charge determines the proper suction pressure of any air conditioning or refrigeration system.
22. How do motion detectors work?
Motion detectors work to help with construction work.
23. If the black box flight recorder is never damaged during a plane crash, why not the whole airplane made out of that stuff?
The SR-71 was made mostly out of Titanium (very high strength to weight ratio) and it got off the ground fine. In addition, a two-seat airplane cost $33 million in 1960s dollars, so no one would ever be able to afford an airliner made out of it.
24. How do you repair a hydraulic jack?
In general, it seems simple: polishing scored cylinders and pistons, replacing worn seals, replacing excessively worn or damaged parts, etc. However, for an ordinary person, the problem I have run into is finding a readily accessible source of parts, as the hydraulic repair industry seems to be a closed fraternity.
25. Does the position of a chicken egg affect the amount of weight it can withstand?
Yes. Lying on its side, it will break with very little pressure. That is why, when you break an egg, you always strike the side.
26. Where do you put the oil in a compressor?
In the reciprocating compressors, you fill the crankcase with the lubricante.
In screw compressors, there is a reservoir to separate oil from compressed air, that reservoir works as the oil sump of the screw compressor.
27. What is a pneumatic system?
Pneumatic system is a system that uses air to power something. For instance, have you seen the tube systems at bank drive-up tellers? Air is used to push the tubes back and forth from the teller to the customer.
Air is also used to power drills, sanders, grinders, and the like at garages and car body shops.
28. What kinds of pipes are used for steam lines?
Normally galvanized pipes are not used for steam. Mild steel with screwed or welded fittings are the norm. Pressure and temperature are very important factors to be considered in what type of materials to be used. Steam even at low pressures can be extremely dangerous.
29. What is the difference between shear center flexural center of twist and elastic center?
The shear center is the centroid of a cross-section. The flexural center is the center of twist, which is the point on a beam that you can add a load without torsion. The elastic center is located at the center of gravity. If the object is homogeneous and symmetrical in both directions of the cross-section then they are all equivalent.
30. What is ferrite?
Magnetic iron rock
31. What is the difference between projectile motion and a rocket motion?
A projectile has no motor/rocket on it, so all of its momentum is given to it as it is launched. An example of a projectile would be pen that you throw across a room.
A rocket or missile does have a motor/rocket on it so it can accelerate itself while moving and so resist other forces such as gravity.
32. Is shear thinning fluids and the linear viscoelastic fluids are the same?
No
33. What is the difference between the flight of a plane and a helicopter?
Both use the pressure difference caused by air moving over the wings at different speeds to generate lift a plane by moving those wings in the direction of travel, a helicopter by spinning the "wings" around at high speed.
34. What is jet plane?
An aircraft powered by a jet engine.
35. How does length and initial angle affect the period in a simple pendulum?
The longer the pendulum is the greater the period of each swing. If you increase the length four times, you will double the period.
It is hard to notice, but the period of a pendulum does depend on the angle of oscillation. For small angles, the period is constant and depends only on the length of the pendulum. As the angle of oscillation (amplitude) is increased, additional factors of a Taylor approximation become important. (T=2*pi*sqrt (L/g) [1+theta^2/16+...] and the period increases.
Interestingly, if the pendulum is supported by a very light wire then the mass of the object at the end of the pendulum does not affect the period. Obviously, the greater the mass, the less any air friction, or friction at the pivot will slow the pendulum. Also interestingly, the pendulum period is dependant on the force of gravity on the object (g). One must not assume that g is constant for all places on Earth.
36. How does a Coal Power station produce electricity?
A fossil fuel power plant (FFPP) (also known as steam electric power plant in the US, thermal power plant in Asia, or power station in the UK) is an energy conversion center designed on a large scale for continuous operation. Just as a battery converts relatively small amounts of chemical energy into electricity for temporary or intermittent use, the FFPP converts the energy stored in fossil fuels such as coal, oil, or natural gas successively into thermal energy, mechanical energy, and finally electric energy for continuous use and distribution across a wide geographic area.
Usually, the coal is utilized to convert water into steam in boilers (thermal energy). The steam is then used to drive steam turbines (mechanical energy). The turbine shaft is coupled to a generator shaft, which generates electricity.
37. What is a cotter joint?
These types of joints are used to connect two rods, which are under compressive or tensile stress. The ends of the rods are in the manner of a socket and shaft that fit together and the cotter is driven into a slot that is common to both pieces drawing them tightly together. The tensile strength of the steel is proportionate to the strength needed to offset the stress on the material divided by the number of joints employed.
38. What are the thermal conductivity properties of brass?
109 W/ (m*K) @ 300K
39. What is the gas constant R for air?
Air gas constant is Rair=R/28.97=0.2869 (J/g K) = 286.9 (J/kg K)
40. What is the alloy of tin and lead?
A tin and lead alloy is commonly called solder. Usually solder is a wire with a rosin core used for soldering. The rosin core acts as a flux.
41. What does F.O.F. stand for in piping design?
FOF stands for Face of Flange. A flange has either of the two types of faces:
a) Raised face
b) Flat face
The F.O.F is used to know the accurate dimension of the flange in order to avoid the minute errors in measurement in case of vertical or horizontal pipelines.
42. Why is the suction pipe of vapor compression and refrigeration system insulated?
The vapor compression and refrigeration system is used to minimize sweating of the air around the pipe. When the air is exposed to a cool surface, its water vapor condenses.
43. What is the full form of WCB in ASTM?
American Society for Testing and Matreails
44. What is the main purpose of an airspeed indicator in an aircraft?
The primary purpose of an airspeed indicator in an aircraft is to give the pilot some sense of how fast the aircraft is moving. A pitot tube, which is a forward pointing hollow tube that is mounted on the plane, is pressurized by the force of the air the plane encounters as it flies. This air pressure is compared to a static reference, and the difference is proportional to the airspeed. The faster the plane moves, the higher the pressure in the Pitot tube, and the greater the difference between that and the reference. All that will result in higher indicated air speed. There are some issues associated with the accuracy of the system (like when the plane is flying into a headwind), and information on. The pictures are informative, and a reader can pick up a handful of specialized terms relating to the device and the principles upon which it operates.
45. What is a uniformly distributed load?
A UDL or uniformly distributed load is a load, which is spread over a beam in such a way that each unit length is laded to the same extent.
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46. What are the differences between pneumatics and hydraulics?
a) Working fluid: Pneumatics use air, Hydraulics use Oil
b) Power: Pneumatic power less than hydraulic power
c) Size: P components are smaller than H components
d) Leakage: Leaks in hydraulics cause fluid to be sticking around the components. In pneumatics, air is leaked into the atmosphere.
e) Pneumatics obtain power from an air compressor while hydraulics require a pump
f) Air is compressible, hydraulic oil is not
47. What is enthalpy?
Enthalpy is the heat content of a chemical system.
48. What is a positive displacement pump?
A positive displacement pump causes a liquid or gas to move by trapping a fixed amount of fluid or gas and then forcing (displacing) that trapped volume into the discharge pipe. Positive displacement pumps can be further classified as either rotary-type (for example the rotary vane) or lobe pumps similar to oil pumps used in car engines. These pumps give a non-pulsating output or displacement unlike the reciprocating pumps. Hence, they are called positive displacement pumps.
49. Why would you use hydraulics rather than pneumatics?
Hydraulics is suitable for higher forces & precise motion than pneumatics. This is because hydraulic systems generally run at significantly higher pressures than pneumatics systems. Movements are more precise (repeatable) because hydraulics uses an incompressible liquid to transfer power whilst pneumatics uses gases.
Pneumatic systems have some advantages too. They are usually significantly cheaper than hydraulic systems, can move faster (gas much less viscous than oil) and do not leak oil if they develop a leak.
50. What is the formula for Heat loss in a pipe?
Pipes are generally cylindrical in structure of amount of heat loss through pipe is given by the formula
Q= 2 pi k L (T1-T2)/ln (r2/r1)
Where
k=conductivity of material of which pipe is made
T1= temperature of inside layer pipe
T2=temperature outside layer of pipe
L= length of pipe
r1= inner radius
r2=outer radius
ln=natural logarithm
pi=22/7
The above condition applies for steady state flow, single layer over cylinder and neglecting conductivity
To take conductivity into account term Qmust be added
Q*=2 pi L {r1 hi (Ti-T1) +r2 ho (T2-To)}
hi=convective coefficient for inside layer
ho=convective coefficient for outside layer
Ti= temperature of inside space of pipe
To=temperature of outside space of pipe
51. What was the spinning jenny?
The spinning jenny is a multi-spool spinning wheel. It was invented circa 1764 by James Hargreaves in Stanhill, near Blackburn, Lancashire in the north west of England (although Thomas Highs is another candidate identified as the inventor).
52. Who invented the four-stroke engine?
Nikolavs August Otto, German
53. What is meant by payload for aircraft?
The payload is the cargo that it carries.
54. Who invented springs?
Rewat
55. How fast is a jet plane?
Fighter jet aircraft fly at speeds in the low mach numbers. Mach 1 is roughly 750 miles per hour, give or take, and military jets can fly at well over a thousand miles per hour. Back in the day (July of 1976), the SR-71 set the jet speed record. Radar clocked the thing at 2242 mph. Oh, and the record still stands. This highly sensitive aircraft project probably holds back data that would top this figure, but the information will not be coming out soon if it exists. The Blackbird is the answer to your prayers. As a caveat, there is a much faster jet called a scramjet, but it is unmanned. The NASA X-43A can hit Mach 9.6, which is about 7300 miles per hour.
56. What are the uses of windmill?
Windmills were traditionally used for processing grains, later they started to be used for electricity production as well. Windmills can also be used to pump water.
57. What is isometric drawing?
It is a 3-D drawing used by draftsmen, architects etc
58. How does iron ore turn into steel?
To make Steel, Iron Ore is refined into iron and all the carbon is burned away using very high heat (Bessemer). A percentage of Carbon (and other trace elements) are added back to make steel.
59. What is the world is hardest metal?
Rhenium diboribe
60. What is a machine shop?
A facility that uses machines to fabricate devices from stock raw materials or to modify mechanisms based upon provided specifications. Also, know as "Back" Shops.
The common machines in a machine shop are a lathe, a drilling m/c, a miller, a shaper/planer, grinding machine and so on.
1. What are the advantages of gear drive?
In general, gear drive is useful for power transmission between two shafts, which are near to each other (at most at 1m distance). In addition, it has maximum efficiency while transmitting power. It is durable compare to other such as belts chain drives etc. You can change the power to speed ratio.
Advantages: -
It is used to get various speeds in different load conditions.
It increases fuel efficiency.
Increases engine efficiency.
Need less power input when operated manually.
62. Why is thick steel wire stronger than thin steel wire?
The material will yield when stress reaches a critical value.
Stress = Load / Area
Thick steel wire is stronger than thin steel wire because there is more cross sectional area in the thick wire. Although the material's strength in load per unit area would be the same, the ultimate load that the wire can sustain would be more in the thick wire.
A simple way of looking at it is to imagine a thick wire as a number of thin wires stuck together. If a thin wire can support a mass of 1kg then 2 thin wires can support 2kg. A wire which is twice as thick (twice the cross sectional area) can also support 2kg.
63. What is the coefficient expansion of transformer oil?
Transformers can be filled with various types of Refined Mineral Oil. That coefficient is something you would find in specifications of the supplier.
64. What is a clock maker called?
A watchmaker or clockmaker is called a horologist.
65. What are the types of sensors and their explanation?
There are many types of sensors. They are used to measure and/or detect a huge variety of conditions including temperature, pressure, level, humidity, speed, motion, distance, light, or the presence/absence of an object and many other types.
Sensors in some cases react to the environment in which they are placed and this reaction is used to measure the property being sensed. For example, a common temperature detector is known as an RTD (resistance temperature detector) and this contains a platinum wire. The electrical resistance of the wire changes with temperature so how the resistance changes can be used to measure the temperature.
Many sensors use this type of principle where the variation of an electrical property of a sensing element is a measure of a property being sensed.
Other types of sensors emit a signal and either measure how the area reacts to the emission or measure the reflection of the signal bouncing off an object in front. Inductive proximity sensors are one of the commonest sensors in use today. They emit a small electromagnetic field and use this to sense the properties of the area in front of the sensor.
66. What is 1810 stainless steel?
1810 Stainless Steel is the European grade that is equivalent to AISI 304 Stainless Steel. It is the most common stainless steel going. Here is the rundown:
Fe, <0.08% C, 17.5-20% Cr, 8-11% Ni, <2% Mn, <1% Si, <0.045% P, <0.03% S
67. How is natural gas better than LPG?
Without getting into the chemistry and physics of the two different types of gases, natural gas has a higher but output than liquid propane gas. In other words, higher the available energy output/more energy is efficient.
68. How can heat be applied to acrylic?
In most hardware stores, you can find what has called a Heat Gun. Hold the heat gun about 6inches away from the acrylic you intend on bending say the bumper on a car. They are plastic these days, but will melt when you apply heat to them. Using a cold scraper, you can usually mold two pieces back together using the heat gun.
69. Did Elevation affect weight?
The acceleration of Gravity is less, as you get further away from the center of the earth. This would cause you to weigh less. The equation for the force of gravity is GMm/(R^2). Where G is the universal Gravity Constant which is something like 6.67x10^ (-11) and M is the mass of the earth, and m is the mass of the weight being measured. R is the distance from the center of the earth that increases as you increase in altitude.
70. Which conducts heat faster steel copper or brass?
Copper conducts heat faster than steel or brass. Any material that is good for conducting heat is also good for electricity in most cases. Wood terrible for transferring heat thus is also insulator for electric.
71. What is the Device that converts sound energy into mechanical energy?
Sound energy is mechanical energy. No devices are required to make a conversion.
72. What is a mechanism?
A mechanism is a system of moving parts that changes an input motion and force into a desired output motion and force.
73. Accelerometers measure acceleration. How do you measure the moment of inertia?
You calculate it using your moment of inertia equations corresponding to the geometry of the object. There is no simple device I do not think that you can buy to just measure it.
74. Who built the first rocket that Robert Goddard invented?
Goddard built his own early rockets.
75. What is a slined joint?
Cotter Pin
76. How pipe flanges are electrically insulated?
Pipe flanges are protected from corrosion by means of electrolysis, with dielectric flanges. The piping system is electrically insulated by what is called a sacrificial anode. A bag of readily corrodible metal is buried in the ground with a wire running from the pipe to the bag so that the sacrificial anode will corrode first. If any electrical current charges the pipe, it also serves as a ground.
77. Why would some industries select pneumatics over hydraulic?
Actually, there is need for air reservoir in industrial pneumatics systems. Hydraulics can handle more powerful applications than pneumatics for the same overall dimensions, or can be more compact for the same power.
78. What is a Process Flow Diagram?
A Process Flow Diagram (or System Flow Diagram) shows the relationships between the major components in the system. It also has basic information concerning the material balance for the process.
79. How do you convert 95 feet into square feet?
You cannot convert feet into square feet; they are two entirely different and incompatible units. Converting feet to square feet is like converting apples to oranges.
A linear foot is a unit of distance. A square foot is a unit of area. If you have a rectangular surface, you can compute the area in square feet by multiplying the length in feet by the width in feet. For example, a rectangular patio that is 12 feet wide by 15 feet long has an area of 12 x 15 = 180 square feet.
80. What is difference between mill and mill-drill?
Today many manufactures are combining machines; a mill/drill is one of these. It is a combination of a drill and a mill, a mill removes stock from material (usually metal, but not limited just to metal, it depends on your application), you use fluted cutters such-as end mills. The drill aspect of the machine is just that it drills holes, with the proper speed for the right size drill.
81. Where pneumatic system is used?
Any system needs redundancy in work needs pneumatics, because the compressor of the pneumatic system has periodical operations (intermittent work, not as hydraulic pump). The compressed air could be accumulated in tanks with high pressures and used even if the compressor failed.
82. What is brain of the computer?
The processor (or CPU) is the brain of the computer. This is the part, which does all the "thinking", i.e. maths.
There is no information stored in the CPU, the information is held in the hard disk, and is fished out, acted on by the CPU, and so on.
83. What is a vee used for on the Vee Block?
It holds round/cylindrical material. It is usually used to judge the cylindricity of the cylindrical material.
Normally 90 degrees vee can be used for the marking of the cylindrical cross section surface, level checking.
84. How many litres did 1 cubic meter contains?
1000 litre in a cubic meter
85. What is the weight of 1m3 of seawater?
1 m^3 = 1000 lits
And 1 lit = 1 kg (approx)
Therefore 1 m^3 = 1000 kg (approx)
86. In 1983 what changed about the length of the meter?
The French were the first to define the length of a meter by using an alluminium/platinum alloy bar of a meter length at 25 degrees Celsius. This however is very inaccurate for quantum measurements, as the length of the bar would change two much depending on how you hold it. A better measurement found in 1983 is the distance that light travels in a vacuum in 1/229,792,458ths of a second. (For those of us with a decent knowledge of relativity that measurement is taken in the rest frame). Crazy I know but at least this way any body in a good physics lab can reproduce this distance without the use of some silly French rod.
87. What are the advantages of powder metallurgy?
Power metallurgy is much faster production while holding closer sizes.
88. What are examples of a first class lever?
Examples of some first class levers are scissor, seesaw, hammer, and wrench.
89. How does a boat measure speed?
Knots one nautical mile per hour there are 1 1/8 of a nautical mile in a statute mile
Originally measured by throwing a piece of wood attached to a piece of rope over the back of a boat and counting how many knots went past in a given time.
These days it is more normally measured by:
a) Using a pitot static tube which measure difference in pressure and uses Bernoulli’s equation to find the velocity.
b) Some form of propeller (technically impeller) which is suspended under the boat. The passing water turns, the speed of rotation is measured, and this gives you the speed of the boat.
c) Using ultrasonic to measure the speed, that small bubbles of air in the water passing under the boat go past.
90. What is a steam turbine diaphragm?
Steam turbine comprises of stages, number and size of the stages depends upon the break horsepower of the turbine.
The stage has set of moving and fixed blades. The moving blades are attached to the rotor while the stationary blades are called Diaphragm.
The diaphragm guides the steam to glide over the moving blades for producing rotary motion.
91. What is wrap-around?
The main purpose of a wrap-a-round is to make a straight line around a pipe to aid in cutting the pipe to its proper length. It is used mostly as a template or a straight edge.
92. What instrument in a car measures its speed?
The speedometer and speedometer cable tells the driver how fast the vehicle is going.
What has called a Hall-Effect sensor is used. It uses the principle of magnetic inductance. When a magnetic flux passes through coils of wire, voltage is generated. To use this effect, a magnet is placed in the cars differential. The sensor then can tell when the magnet comes around by a spike in voltage. Since there is a constant amount the car moves with each differential rotation, and with the time between voltage spikes, you can easily divide to get the speed.
This is why changing your cars tires will affect your speedometer. Your car assumes that car moves a certain amount with each differential rotation. If you have larger tires on, then each differential rotation (and axle rotation) your car moves further, and you will move faster than indicated.
93. Can an airplane fly without a tail?
There are a number of aircraft, which are designed without tail assemblies. As for aircraft designed with a tail assembly that may lose it in flight, that's problematic for the flight crew, but there have been instances of portions of tail assemblies being lost due to structural failure or accident that have managed to successfully land.
94. Will going from a 3 tap to a 6 tap increase water pressure?
No, the pressure will be the same, you will get more volume only if your pumps can handle the gpm, to increase pressure you may need a booster pump or a single pump that is rated for your needs.
95. Why gas containers are mostly cylindrical in shape?
The most efficient shape for withstanding high pressure is a sphere but that would be costly to manufacture. A cylinder with a domed top and a domed bottom (look underneath, the flat base is actually welded around the outside, the bottom of the gas container is actually domed) is a much cheaper shape to manufacture whilst still having good strength to resist the internal gas pressure.
96. When was the first space rocket built?
1890
97. How does a hammer mill work?
Big hammers (not the kind you pound nails with) spin out with centrifugal force and beat whatever it is you are grinding into smaller pieces.
98. What are some mechanical laboratory apparatuses?
Welding machine
99. How does a modern submarine move?
Modern submarines move by using some motor to drive a propeller (called a screw). The big u-boats have nuclear reactors that heat water to make steam and have steam turbines that drive the screw through a big reduction gear. Many smaller submarines use a battery bank and electric motors with little propellers on them to move.
100. Is a diesel engines maximum rpm limited by the diesel burn rate?
Yes. In practice however, the maximum rpm is usually limited by the construction of the rotating assembly and the high-pressure injection parts.
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