important questions about interview of mechanical engineer

1. Mechanical Engineering Interview questions and answers
1. What is your favourite subject in Mechanical engineering?
Ans:
Normally they are looking for the subject in which their company is based on.
Do not worry if you tell other than the subject of company. Be true to yourself.
You will be trained once you will be recruited.
2. What was your project during Mechanical engineering?
Ans:
They will looking for leadership. If you did project in group work, they will find
out your leadership quality by related question.
3. What safety precautions should be observed while working in the workshop
?
Ans:
Keep shop floor clean, free from oil and other slippery materials.
Wear proper dress and avoid loose clothing and loose hair.
Wear shoes and avoid chapels.
Avoid playing, loose talk and funning inside the shop floor.
Keep good housekeeping and put all unnecessary items and rejected
items in scrap box.
Learn everything about the machine before starting and clear all the
doubts.
Keep a safe distance from rotating and sliding parts.
Never store inflammable materials inside or around the shop.
Never play with electricity, fire, parts with sharp edge etc.
Keep fire buckets and extinguishers ready for use.
4. What are the precautions to be taken to avoid fire ?
Ans:
The buckets along with sand should be placed inside the workshop.
Switches and other electrical parts must be made of fireproof material.
Carbon dioxide gas should be place at required points in special
containers.
Fire extinguishers of suitable type should be placed at accessible
places.
5. What do you mean by First Aid ?
Ans:
First Aid is immediate and temporary care given to a person who affected
accidental injury or a sudden illness before the arrival of doctor.
6. What is a Drawing ?
Ans:
It is a graphical representation of a real thing to define and specify the shape
and size of a particular object by means of lines.
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2. 7. What is Engineering Drawing ?
Ans:
A drawing which is worked out an engineer for the engineering purpose is
known as Engineering Drawing.
8. Explain briefly the following lines used in Engineering drawing ?
Ans:
(a)Dimension Lines
Dimension lines are the thin lines used to indicate extents and direction of
dimension. These are terminated with arrowheads.
(b)Extension Lines
Extension lines are also thin lines and it used to indicate the termination of a
dimension.
(c)Leaders
Leaders are used to direct notes or identification symbols to feature on the
drawing.
9. Difference between 'Thermodynamics and Heat Transfer'?
Ans:
Thermodynamics mainly deals with the transfer of energy in form of heat or
work between systems and surroundings with other systems in form of either
heat or work in equilibrium conditions. When there is change in one state,
which was in equilibrium state and starting to change in other equilibrium
state, this information helps to determine heat or work interactions due to this
process. While
Heat transfer deals with non equilibrium heat exchange or transfer due to
temperature gradient while in thermodynamics, during thermal equilibrium (No
temperature gradient) no heat exchange is possible.
10. Explain in an orderly manner how the force in the member of a truss be
detected using the method of joint.
Ans:
The steps required to calculate the force are as follows:
The reaction at the support has to be first calculated.
Once the reaction is calculated the direction of force of the member is
made to make it tensile. On getting the result to be negative the
direction assumed is wrong and this implies the force being
compressive in nature.
A joint needs to be selected whose 2 members are not known. The
lami's theorem is used on the joint on which less than three forces are
acting.
After the above process is complete the free body diagrams of the joint
needs to be made. Since the system is in equilibrium the condition of
Summation of V and H must result in zero.
After the above step the resolution of forces method needs to be used
on the joint on which more than 4 forces are acting.
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3. 11. What is mechanism?
Ans:
A mechanism is an assembly of different parts which perform a complete
motion and is often part of a machine.
12. What is annealing?
Ans:
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.
13. What is ductile-brittle transition temperature?
Ans:
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.
14. Difference between tempering and annealing
Ans:
Annealing is a process in which work piece is heated up to certain
temperature to get desired changes in grain or micro-structure and then
allowed to cool slowly in order to relieve the stresses during work treatment.
While tempering is a process wherein hardness and elasticity or ductility can
be regain by use of heating and cooling cycle till desired properties can be
obtained.
15. What are the advantages of gear drive?
Ans:
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.
16. What is isometric drawing?
Ans:
It is a 3-D drawing used by draftsmen, architects etc
17. What is a Process Flow Diagram?
Ans:
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.
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4. 18. Is it the stress that, produces strain or strain produces stress?
Ans:
A Force applied to an object will cause a displacement. Strain is effectively a
measure of this displacement (change in length divided by original length).
Stress is the Force applied divided by the area it is applied. (E.g. pounds per
square inch)
Therefore, to answer the question, the applied force produces both “Stress
and Strain”. “Stress and Strain” are linked together by various material
properties such as Poisson's ratio and Young's Modulus.
19. What are the points in the stress strain curve for steel?
Ans:
Proportional limit, elastic limit or yield point, ultimate stress and stress at
failure.
20.State Newton's three laws of Motion.
Ans:
The law of inertia: Every object in a state of uniform motion tends to
remain in that state of motion unless an external force is applied to it.
Acceleration is produced when a force acts on a mass. The greater the
mass (of the object being accelerated) the greater the amount of force
needed (to accelerate the object). Force=Mass times acceleration.
For every action there is an equal and opposite reaction.
21.State the laws of thermodynamics?
Ans:
Thermodynamics is a physical science which studies the interrelation between
heat, work and the internal energy of any system. Thermodynamics helps
study all the systems of mechanical engineering. There are three laws of
thermodynamics.
First Law: Energy can be neither created nor destroyed. It can only change
forms. In any process in an isolated system, the total energy remains the
same.
Second Law: The second law of thermodynamics states that the entropy of
any isolated system not in thermal equilibrium almost always increases.
Third Law: As temperature approaches absolute zero, the entropy of a system
approaches a minimum.
22.What is Hess law?
Ans:
According to the Hess law the energy transfer is simply independent of the
way being followed. If the reactant and the product of the whole process are
the same then same amount of energy will be dissipated or absorbed.
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5. 23.Explain what is torque?
Ans:
Torque is the force that causes rotation. It is a measure of how much force is
acting on an object making it rotate.
24.What is the difference between torque and power?
Ans:
While power determines the speed of a vehicle, torque determines the time in
which that speed can be reached. The greater the torque figure, the faster the
acceleration. The more torque in the engine, the faster you accelerate. Power
is the rate at which work is done, so it is basically the potential of the engine.
25. What is fuel ratio ?
Ans:
Fuel ratio is the ratio of its % age of fixed carbon to volatile matter.
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