Freshers Mechanical Engineers Interview Questions & Answers

26. For what purpose the bifiler suspension system used ?

Ans:  It is used to determine moment of inertia.

27. How forced vibrations are dependent on natural frequency ?

Ans:  They are independent.

28. Out of involute and cycloidal profile, which has constant pressure angle throughout gear tooth contact and which requires exact centre distance ?

Ans:  In involute profile, pressure angle is same throughout enagement and cycloidal profile requires exact centre distance between two gears.

 29. On which parameters depends the value of gyroscopic couple ?

Ans:  It depends upon M.I. of rotor, spinning speed, and angular speed of precession.

30. What is the difference between swaying couple and hammer blow ?

Ans:  Swaying couple is produced due to unbalanced parts of the primary disturbing forces act¬ing at a distance between the line of stroke of the cylinders. Hammer blow is the maximum value of the unbalanced vertical force of the balance weights.

31. For a flat pivot what is the ratio of frictional moment for uniform pressure vs uniform rate of wear ?

Ans:  4 : 3.

 32. Explain difference between simple mechanism and compound mechanism.

Ans:  Simple mechanism has upto four links and compound mechanism has more than four
links.

 33. What is the difference between plane and spatial mechanism ?

Ans:  In plane mechanism all the links lie in the same plane whereas in spatial mechanism links lie in different planes.

34. How many degrees of freedom are there in a constrained mechanism ?

Ans:  One.

35. What is Klein’s construction ?

Ans:  It is a graphical procedure of drawing acceleration diagram for a slider crank mechanism.

36. What type of mechanism is constituted by Peaucellier, Hart and Scott-Russel mechanism ?

Ans:  Straight line mechanism.

 37. What is the difference between fast pulley and loose pulley ?

Ans:  Fast pulley transmits power and loose pulley does not.

38. What is the value of damping factor for a critically damped system ?

Ans:  Unity.

39. What are the values of amplitude of vibration at node and antinode ?

Ans:  Zero and maximum.

40. What is the value of damping ratio for under-damped system ?

Ans:  Less than unity.

41. On what factors the critical speed of a rotating shaft depends ?

Ans:  Mass and stiffness.

42. What is the damping ratio for non-oscillating system and under-damped system ?

Ans:  More than unity and less than unity respectively.

43. What is fundamental frequency ?

Ans:  It is the minimum frequency in the system.

 44. Give three active and passive transducers ?

Ans:     Active transducers                            Passive transducers
1.    Thermocouples and Thermopiles           Resistive transducers
2.    Moving coil generators                          Inductive transducers
3.    Photovoltaic cells                                  Capacitive transducers

 46. Which is best suited bearing for combined thrust and radial loads at high speeds ?

Ans:  Deep groove ball bearings.

47. Which parameter determines the life expectancy of ball/roller bearing ?

Ans:  Basic dynamic loading.

 48. Which bearing is suitable for combined radial and axial loads ?

Ans:  Taper roller bearing.

49. Explain the difference between hydrostatic and hydrodynamic bearings ?

Ans:  In hydrostatic bearings, lubricant is supplied at high pressure to lift the shaft. In hydro-dynamic bearings the hydrodynamic pressure is generated due to rotation of the journal.

50. What is the ratio of frictional torque produced for uniform wear to frictional torque produced for uniform pressure ?

Ans:  3/4.