1000+ Theory of Machines Multiple Choice Question Answer [Solved]

1. The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft, and tan ? = Coefficient of friction between the shaft and bearing)
A. r sin?
B. r cos?
C. r tan?
D. (r/2) cos?
Answer : A

2. When a slider moves on a fixed link having curved surface, their instantaneous centre lies
A. On their point of contact
B. At the centre of curvature
C. At the centre of circle
D. At the pin joint
Answer : B

3. The coriolis component of acceleration leads the sliding velocity by
A. 45°
B. 90°
C. 135°
D. 180°
Answer : B

4. ________ is an inversion of Double slider crank chain.
A. Coupling rod of a locomotive
B. Scotch yoke mechanism
C. Hand pump
D. Reciprocating engine
Answer : B

5. The sensitiveness of the governor __________ as the speed range decreases.
A. Remains unaffected
B. Decreases
C. Increases
D. None of these
Answer : C

6. In order to double the period of a simple pendulum, the length of the string should be
A. Halved
B. Doubled
C. Quadrupled
D. None of these
Answer : C

7. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform wear, is
A. (1/2). ? W cosec ? (r? + r?)
B. (2/3).? W cosec ? (r? + r?)
C. (1/2). ? W cosec ? [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W cosec ? [(r?³ - r?³)/(r?² - r?²)]
Answer : A

8. The magnitude of velocities of the points on a rigid link is
A. Directly proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre
B. Directly proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre
C. Inversely proportional to the distance from the points to the instantaneous centre and is parallel to the line joining the point to the instantaneous centre
D. Inversely proportional to the distance from the points to the instantaneous centre and is perpendicular to the line joining the point to the instantaneous centre
Answer : D

9. A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc
A. The reaction on me inner wheels increases and on the outer wheels decreases
B. The reaction on the outer wheels increases and on the inner wheels decreases
C. The reaction on the front wheels increases and on the rear wheels decreases
D. The reaction on the rear wheels increases and on the front wheels decreases
Answer : B

10. The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because
A. Whole of the mechanism in the Ackerman steering gear is on the back of the front wheels
B. The Ackerman steering gear consists of turning pairs
C. The Ackerman steering gear is most economical
D. Both (A) and (B)
Answer : D

11. When the nature of contact between the elements of a pair is such that it can only slide relative to the other, the pair is known as a
A. Screw pair
B. Spherical pair
C. Turning pair
D. Sliding pair
Answer : D

12. The rotating shafts tend to vibrate violently at whirling speeds because
A. The system is unbalanced
B. Bearing centre line coincides with the axis
C. The shafts are rotating at very high speeds
D. Resonance is caused due to the heavy mass of the rotor
Answer : D

13. If the number of links in a mechanism is equal to l, then the numbers of possible inversions are equal to
A. l - 2
B. l - 1
C. l
D. l + 1
Answer : C

14. Klein's construction is useful to determine
A. Velocity of various parts
B. Acceleration of various parts
C. Displacement of various parts
D. Angular acceleration of various parts
Answer : B

15. The frictional torque transmitted in a flat pivot bearing, considering uniform pressure, is (where ? = Coefficient of friction, W = Load over the bearing, and R = Radius of bearing surface)
A. (1/2) ? W R
B. (2/3) ? W R
C. (3/4) ? W R
D. ? W R
Answer : B

16. Which of the following statement is correct?
A. The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.
B. The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.
C. The velocity of a particle moving with simple harmonic motion is zero at the mean position.
D. The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.
Answer : A

17. A shaft carrying three rotors will have
A. No node
B. One node
C. Two nodes
D. Three nodes
Answer : C

18. For an involute gear, the ratio of base circle radius and pitch circle radius is equal to
A. sin?
B. cos?
C. sec?
D. cosec?
Answer : B

19. A torsional system with discs of moment of inertia I? and I? as shown in the below figure, is gear driven such that the ratio of speed of shaft B to shaft A is 'G'. Neglecting the inertia of gears, the equivalent inertia of disc on shaft B at the speed of shaft A is equal to
A. G.I?
B. G².I?
C. I?/G
D. I?/G²
Answer : B

20. When a body is subjected to transverse vibrations, the stress induced in a body will be
A. Shear stress
B. Bending stress
C. Tensile stress
D. Compressive stress
Answer : B

21. The relation l = (2/3).(j + 2) apply only to kinematic chains in which lower pairs are used. This may be used to kinematic chains in which higher pairs are used, but each higher pair may be taken as equivalent to
A. One lower pair and two additional links
B. Two lower pairs and one additional link
C. Two lower pairs and two additional links
D. Any one of these
Answer : B

22. A rotor which is balanced statically but not dynamically is supported on two bearings L apart and at high speed of the rotor, reaction on the left bearing is R. The right side of the bearing is shifted to a new position 2L apart from the left bearing. At the same rotor speed, dynamic reaction on the left bearing in the new arrangement will
A. Remain same as before
B. Become equal to 2R
C. Become equal to R/2
D. Become equal to R/4
Answer : A

23. The type of coupling used to join two shafts whose axes are neither in same straight line nor parallel, but intersect is
A. Flexible coupling
B. Universal coupling
C. Chain coupling
D. Oldham's coupling
Answer : B

24. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a left turn. The effect of gyroscopic couple acting on it will be
A. To raise the bow and stern
B. To lower the bow and stern
C. To raise the bow and lower the stern
D. To raise the stern and lower the bow
Answer : C

25. The secondary unbalanced force is __________ the primary unbalanced force.
A. One-half
B. Two-third
C. n times
D. 1/n times
Answer : D

26. The indicator using Watt mechanism is known as
A. Thompson indicator
B. Richard indicator
C. Simplex indicator
D. Thomson indicator
Answer : B

27. When the crank is at the inner dead centre, in a reciprocating steam engine, then the acceleration of the piston will be
A. ?²r. (n + 1)/n
B. ?²r. (n - 1)/n
C. ?²r. n/(n + 1)
D. ?²r. n/(n - 1)
Answer : A

28. A kinematic chain is known as a mechanism when
A. None of the links is fixed
B. One of the links is fixed
C. Two of the links are fixed
D. None of these
Answer : B

29. In steady state forced vibrations, the amplitude of vibrations at resonance is __________ damping coefficient.
A. Equal to
B. Directly proportional to
C. Inversely proportional to
D. Independent of
Answer : C

30. For simple harmonic motion of the of follower, a cosine curve represents
A. Displacement diagram
B. Velocity diagram
C. Acceleration diagram
D. All of the above
Answer : C

31. In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon
A. Total lift, total angle of lift, minimum radius of cam and cam speed
B. Radius of circular arc, cam speed, location of centre of circular arc and roller diameter
C. Mass of cam follower linkage, spring stiffness and cam speed
D. Total lift, centre of gravity of the cam and cam speed
Answer : A

32. The radial distance from the top of a tooth to the bottom of a tooth in a meshing gear, is called
A. Dedendum
B. Addendum
C. Clearance
D. Working depth
Answer : C

33. When the sleeve of a Porter governor moves downwards, the governor speed
A. Increases
B. Decreases
C. Remain unaffected
D. First increases and then decreases
Answer : B

34. It is required to connect two parallel shafts, the distance between whose axes is small and variable. The shafts are coupled by
A. Universal joint
B. Knuckle joint
C. Oldham's coupling
D. Flexible coupling
Answer : C

35. The flank of the tooth is the surface of the tooth __________ the pitch surface.
A. Above
B. Below
C. At
D. None of these
Answer : B

36. The instantaneous centre of a rigid thin disc rolling on a plane rigid surface is located at
A. The centre of the disc
B. The point of contact
C. An infinite distance on the plane surface
D. The point on the circumference situated vertically opposite to the contact point
Answer : B

37. Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?
A. Theory of machines
B. Applied mechanics
C. Mechanisms
D. Kinetics
Answer : A

38. A point B on a rigid link AB moves with respect to A with angular velocity ? rad/s. The radial component of the acceleration of B with respect to A, is (where vBA = Linear velocity of B with respect to A)
A. v_BA × AB
B. v_BA /AB
C. v²_BA
D. v²_BA /AB
Answer : D

39. The frictional torque transmitted by a cone clutch is same as that of
A. Flat pivot bearing
B. Flat collar bearing
C. Conical pivot bearing
D. Truncated conical pivot bearing
Answer : D

40. The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as
A. Completely constrained motion
B. Incompletely constrained motion
C. Successfully constrained motion
D. None of these
Answer : A

41. A typewriter mechanism has 7 numbers of binary joints, six links and none of higher pairs. The mechanism is
A. Kinematically sound
B. Not sound
C. Soundness would depend upon which link is kept fixed
D. Data is not sufficient to determine same
Answer : A

42. Cylindrical cams can be classified as
A. Circular
B. Tangent
C. Reciprocating
D. None of the above
Answer : D

43. Crowning on pulleys helps
A. In increasing velocity ratio
B. In decreasing the slip of the belt
C. For automatic adjustment of belt position so that belt runs centrally
D. Increase belt and pulley life
Answer : C

44. The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the centre of gravity is equal to the radius of gyration of the body about its centre of gravity.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : B

45. The periodic time of one oscillation for a simple pendulum is
A. 2?. ?(g/l)
B. (1/2?). ?(g/l)
C. 2?. ?(l/g)
D. (1/2?). ?(l/g)
Answer : C

46. The relative velocity of B with respect to A in a rigid link AB is
A. Parallel to AB
B. Perpendicular to AB
C. Along AB
D. At 45° to AB
Answer : B

47. The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be
A. To dip the nose and tail
B. To raise the nose and tail
C. To raise the nose and dip the tail
D. To dip the nose and raise the tail
Answer : C

48. The face of the tooth is the
A. Surface of the top of tooth
B. Surface of tooth above the pitch surface
C. Width of tooth below the pitch surface
D. Width of tooth measured along the pitch circle
Answer : B

49. Which of the following is an open pair?
A. Journal bearing
B. Ball and Socket joint
C. Leave screw and nut
D. None of the above
Answer : C

50. Coriolis component is encountered in
A. Quick return mechanism of shaper
B. Four bar chain mechanism
C. Slider crank mechanism
D. Both (A) and (C) above
Answer : A