MECHANICAL INTERVIEW QUESTIONS
AND VERIFIED ANSWERS|100%
CORRECT|GRADE A+
1. Explain the second law of thermodynamics - ANSWER The entropy of the universe increases over time
and moves towards a maximum value.
2. What kinds of pipes are used for steam lines? - ANSWER 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.
3. What is the difference between shear center flexural center of twist and elastic center? - ANSWER 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.
4. What is ferrite? - ANSWER Magnetic iron rock
5. What is the difference between projectile motion and a rocket motion? - ANSWER 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.
6. What is a cotter joint? - ANSWER 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.
7. What is the alloy of tin and lead? - ANSWER 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.
, 8. What does F.O.F. stand for in piping design? - ANSWER 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.
9. Explain Otto cycle. - ANSWER Otto cycle can be explained by a pressure volume relationship diagram.
It shows the functioning cycle of a four stroke engine. The cycle starts with an intake stroke, closing the
intake and moving to the compression stroke, starting of combustion, power stroke, heat exchange
stroke where heat is rejected and the exhaust stroke. It was designed by Nicolas Otto, a German
engineer.
10. What is gear ratio? - ANSWER It is the ratio of the number of revolutions of the pinion gear to one
revolution of the idler gear.
11. What is annealing? - ANSWER It is a process of heating a material above the re-crystallization
temperature and cooling after a specific time interval. This increases the hardness and strength if the
material.
12. What is ductile-brittle transition temperature? - ANSWER It is the temperature below which the
tendency of a material to fracture increases rather than forming. Below this temperature the material
loses its ductility. It is also called Nil Ductility Temperature.
13. What is a uniformly distributed load? - ANSWER UDL or uniformly distributed load is a load, which is
spread over a beam in such a way that each unit length is loaded to the same extent.
14. What are the differences between pneumatics and hydraulics? - ANSWER 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
AND VERIFIED ANSWERS|100%
CORRECT|GRADE A+
1. Explain the second law of thermodynamics - ANSWER The entropy of the universe increases over time
and moves towards a maximum value.
2. What kinds of pipes are used for steam lines? - ANSWER 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.
3. What is the difference between shear center flexural center of twist and elastic center? - ANSWER 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.
4. What is ferrite? - ANSWER Magnetic iron rock
5. What is the difference between projectile motion and a rocket motion? - ANSWER 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.
6. What is a cotter joint? - ANSWER 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.
7. What is the alloy of tin and lead? - ANSWER 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.
, 8. What does F.O.F. stand for in piping design? - ANSWER 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.
9. Explain Otto cycle. - ANSWER Otto cycle can be explained by a pressure volume relationship diagram.
It shows the functioning cycle of a four stroke engine. The cycle starts with an intake stroke, closing the
intake and moving to the compression stroke, starting of combustion, power stroke, heat exchange
stroke where heat is rejected and the exhaust stroke. It was designed by Nicolas Otto, a German
engineer.
10. What is gear ratio? - ANSWER It is the ratio of the number of revolutions of the pinion gear to one
revolution of the idler gear.
11. What is annealing? - ANSWER It is a process of heating a material above the re-crystallization
temperature and cooling after a specific time interval. This increases the hardness and strength if the
material.
12. What is ductile-brittle transition temperature? - ANSWER It is the temperature below which the
tendency of a material to fracture increases rather than forming. Below this temperature the material
loses its ductility. It is also called Nil Ductility Temperature.
13. What is a uniformly distributed load? - ANSWER UDL or uniformly distributed load is a load, which is
spread over a beam in such a way that each unit length is loaded to the same extent.
14. What are the differences between pneumatics and hydraulics? - ANSWER 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
