Mechanical Engineering Relevant Interview Questions
1. The point through which whole weight of the body acts, irrespective of its position is called...
Ans. Centre of gravity
2. What is Newtons second law of motion ?
Ans. F= m* a
3. What is the equation of three co planar forces P, Q and R if they act at a point O and also these three forces are in equilibrium?
Ans. P/ sin alpha = Q/ sin beta = R/ sin gamma
4. What is Hess's law?
Ans. According to Hess's law, energy transfer is independent of the path followed.
5. What is a bearing?
Ans. A bearing is a device which reduce friction and provides smooth movement and thereby enhancing the efficiency and speed. A bearing handles load, for different operations.
6. What is the difference between Torque and Power?
Ans. Power is the rate at which work is done. Basically power determines speed of the engine and Torque determines the time in which that speed can be reached.
7. Why do heavy vehicles use Diesel engines ?
Ans. Diesel produces low energy on burning of fuels and so efficiency of the engine increases with load.
8. Why do reheater used in a gas turbine ?
Ans. Reheater increases efficiency of the turbine and increase high thrust.
9. What is DTSI in motorbikes?
Ans. A petrol engine needs higher combustion ration. DTSI system has two spark plugs fixed on top of cylinder which will oprovide twin sparks and thereby increase higher combustion.
10. If compression test is done on Cast iron, then fracture will occur along ......?
Ans. Along an oblique plane
11. At the principal planes...?
Ans. Normal stress is maximum or minimum. Shear stress is zero
12. Shear stresses on mutually perpendicular planes are...?
Ans. Equal
13. The point of application of force of bouyancy on a body is known as..?
Ans. Centre of bouyancy
14. A floating body is in equilibrium when?
Ans. Its metacentre above centre of gravity.
15. A pitot tube is used to measure ?
Ans. Velocity of flow
16. Why is heat treatment done?
Ans. Heat treatment is the process of combinations of operations carried out like cooling and heating to increase desirable properties with out changing its composition.
17. What is a carnot engine?
Ans. A carnot cycle is an imaginary engine, which provides 100% efficiency.
18. What is the use of a scrapper ring ?
Ans. These prevents oil from entering combustion zone by scrapping excess lube oil from cylinder walls.
19. What are journal bearings?
Ans. These bearings are used in low speed and high load applications. These have higher friction force, produce more heat and have large contact surface.
20. What is the difference between Technology and Engineering?
Ans. Engineering is the application of science. Technology shows various methods in engineering. For eg: When building a over bridge we either use a method using beams or hanging bars all these called technology and the equations for calculating loads and stress comes under Civil Engineering.
21. What are the disadvantages of using LPG in automobiles?
Ans. LPG is low cost but, Engine overheat during larger journeys and more heat liberated. LPG fuel reduces engine efficiency. Installation is really difficult.
22. What is the abbreviation of welding rod 7018 ?
Ans. 70- Tensile strength, 1- Welding position, 8- Current flux
23. What is brazing?
Ans. It is the process of joining metals. Brazing is usually at lower temperatures and does not melt base metals. A filler metal is allowed to flow through cavity.
24. What is the difference between stamina and strength?
Ans. Strength is the capability over a short length of time and Stamina is the ability to keep going continously.
25. What is a cotter joint?
Ans. It is used to connect two co- axial rods which are subjected to axial tensile or compressive forces. Shaft is locked in place by using a small pin named as cotter.
26. Why centrifugal pump is called as High discharge pump?
Ans. A centrifugal pump uses centrifugal force to push out the fluid. The liquid entering the pump receives kinetic energy from rotating impeller. The centrifugal action of the impeller accelerates the liquid to high velocity. It discharges liquid in high rate.
27. Which pump is more efficient Centrifugal pump or Reciprocating pump?
Ans. It is centrifugal pump. Flow rate is higher and smooth flow. Low initation cost and requires less space.
28. What is momentum?
Ans. It is the quantity of motion of a moving body, measured as a product of its mass and velocity.
29. What is mean by centroid?
Ans. A centroid is a point in a plane area such that the moment of the area about any axis through that point is zero.
30. What is camber angle?
Ans. Camber angle is the inclination vertical to the steered wheel of an automobile.
31. What is mean by Pascals law?
Ans. It states that pressure exerted anywhere in an incompressible fluid remains the same and is equally transmitted along all directions.
32. What is mean by a streak line?
Ans. A line within a fluid which, at a given instant, is formed by those fluid particles which at some previous instant have passed through a specific point in the fluid.
33. What is mean by viscosity?
Ans. It is the property of a fluid by which offerse resistance to shear or can be simply described as resistance to flow. Unit of viscosity is poise.
34. Explain Bernoullis equation?
Ans. It states that total energy in the steady flow of an incompressible fluid is constant.
35. What is mean by a culvert?
Ans. A drain or a pipe which allows water to flow under a road, railroad or similar construction.
36. What is mean by Froude number?
Ans. It is a dimensionless quantity measuring ratio of inertia force of the fluid element to its weight.
37. What is mean by weber number?
Ans. The ratio between inertial force and surface tension force.
38. What is mean by bouyancy?
Ans. It is the upward force that a fluid exerts on an object which is less denser than itself. It is equal to weight of liquid displaced.
39. What is mean by Hemming?
Ans. A bending operation that bends and folds an edge of metal sheet back upon itself.
40. What is mean by Embossing?
Ans. A metal operation used to create raised surfaces.
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