1000+ Theory of Machines MCQ for SSC Stenographer [Solved]

1. When a point moves along a straight line, its acceleration will have
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : B

2. The relation between the controlling force (Fc) and radius of rotation (r) for a stable spring controlled governor is
A. F_c = ar + b
B. F_c = ar - b
C. F_c = ar
D. F_c = a/r + b
Answer : B

3. The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
A. ?² R cos?
B. ?² (R - r?) cos?
C. ?² (R - r?) sin?
D. ?² r? sin?
Answer : B

4. The lead screw of a lathe with nut forms a
A. Rolling pair
B. Sliding pair
C. Screw pair
D. Turning pair
Answer : C

5. 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

6. A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cos?.t with usual notations. It represents
A. Free vibration with damping
B. Free vibration without damping
C. Forced vibration with damping
D. Forced vibration without damping
Answer : C

7. The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
A. Unbalanced couples are caused only at higher speeds
B. Unbalanced forces are not dangerous at higher speeds
C. Effects of unbalances are proportional to the square of the speed
D. Effects of unbalances are directly proportional to the speed
Answer : C

8. The two elements of a pair are said to form a higher pair, when they
A. Have a surface contact when in motion
B. Have a line or point contact when in motion
C. Are kept in contact by the action of external forces, when in motion
D. Permit relative motion
Answer : B

9. 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

10. In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
A. Less sensitive
B. More sensitive
C. Unaffected of sensitivity
D. Isochronous
Answer : A

11. The included angle for the V-belt is usually
A. 10° to 20°
B. 20° to 30°
C. 30° to 40°
D. 60° to 80°
Answer : C

12. For a kinematic chain to be considered as mechanism
A. Two links should be fixed
B. One link should be fixed
C. None of the links should be fixed
D. There is no such criterion
Answer : B

13. In a four stroke I.C. engine, the turning moment during the compression stroke is
A. Positive throughout
B. Negative throughout
C. Positive during major portion of the stroke
D. Negative during major portion of the stroke
Answer : B

14. 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

15. A chain comprises of 5 links having 5 joints. Is it kinematic chain?
A. Yes
B. No
C. It is a marginal case
D. Data are insufficient to determine it
Answer : B

16. The direction of Coriolis component of acceleration is the direction
A. Of relative velocity vector for the two coincident points rotated by 90° in the direction of the angular velocity of the rotation of the link
B. Along the centripetal acceleration
C. Along tangential acceleration
D. Along perpendicular to angular velocity
Answer : A

17. If D? and D? be the diameters of driver and driven pulleys, then belt speed is proportional to
A. D?/D?
B. D?/D?
C. D?.D?
D. D?
Answer : D

18. Which of the following is an inversion of a single slider crank chain?
A. Pendulum pump
B. Oscillating cylinder engine
C. Rotary internal combustion engine
D. All of these
Answer : D

19. 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

20. To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use?
A. Spur gear B. Spiral gear
C. Bevel gear
D. Worm gear
Answer : D

21. Balancing of rotating and reciprocating parts of an engine is necessary when it runs at
A. Slow speed
B. Moderate speed
C. Highs peed
D. Any one of these
Answer : C

22. The equation of motion for a single degree of freedom system with viscous damping is 4(dx²/dt²) + 9(dx/dt) + 16x. The damping ratio of the system is
A. 9/8
B. 9/82
C. 9/16
D. 9/128
Answer : C

23. In a simple harmonic motion, the velocity vector with respect to displacement vector
A. Is in phase
B. Leads by 90°
C. Leads by 180°
D. Lags by 90°
Answer : D

24. The power from the engine to the rear axle of an automobile is transmitted by means of
A. Worm and worm wheel
B. Spur gears
C. Bevel gears
D. Hooke's joint
Answer : D

25. Which of the following is a higher pair?
A. Turning pair
B. Screw pair
C. Belt and pulley
D. None of the above
Answer : C

26. The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m).(dx/dt) + (s/m).x = 0, if the roots of the equation are __________ then the system will be under damped.
A. Equal
B. Real
C. Complex conjugate
D. None of these
Answer : C

27. The locus of a point on a thread unwound from a cylinder will be
A. A straight line
B. A circle
C. Involute
D. Cycloidal
Answer : C

28. The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as
A. Damping factor
B. Damping coefficient
C. Logarithmic decrement
D. Magnification factor
Answer : D

29. In higher pair, the relative motion is
A. Purely turning
B. Purely sliding
C. Purely rotary
D. Combination of sliding and turning
Answer : D

30. A reed type tachometer use the principle of
A. Longitudinal vibration
B. Torsional vibration
C. Transverse vibration
D. Damped free vibration
Answer : C

31. Which of the following statements regarding laws governing the friction between dry surfaces are correct?
A. The friction force is dependent on the materials of the contact surfaces.
B. The friction force is directly proportional to the normal force.
C. The friction force is independent of me area of contact.
D. All of the above
Answer : D

32. The factional torque for square thread at the mean radius r while raising load W is given by
A. T = W.r tan(? - ?)
B. T = W.r tan(? + ?)
C. T = W.r tan?
D. T = W.r tan?
Answer : B

33. The frequency of oscillation of a compound pendulum is
A. 2?. ?[gh/(k_G² + h²)]
B. 2?. ?[(k_G² + h²)/gh]
C. (1/2?). ?[gh/(k_G² + h²)]
D. (1/2?). ?[(k_G² + h²)/gh]
Answer : C

34. 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

35. In Meyer's expansion valve, the main valve is driven by an eccentric having an angle of advance from
A. 10°-15°
B. 15°-25°
C. 25°-30°
D. 30°-40°
Answer : C

36. The following is the inversion of slider crank chain mechanism
A. Whitworth quick return mechanism
B. Hand pump
C. Oscillating cylinder engine
D. All of the above
Answer : D

37. In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is Constant, then
A. Open belt drive is recommended
B. Crossed belt drive is recommended
C. Both open belt drive and crossed belt drive is recommended
D. The drive is recommended depending upon the torque transmitted
Answer : B

38. The Kutzbach criterion for determining the number of degrees of freedom (n) is (where l = number of links, j = number of joints and h = number of higher pairs)
A. n = 3(l - 1) - 2j - h
B. n = 2(l - 1) -2j - h
C. n = 3(l - 1) - 3j - h
D. n = 2(l - 1) - 3j - h
Answer : A

39. The velocity of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
A. ?R cos?
B. ?(R - r?) cos?
C. ?(R - r?) sin?
D. ?r? sin?
Answer : C

40. The secondary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
A. 0° and 90°
B. 180° and 360°
C. Both (A) and (B)
D. None of these
Answer : C

41. The pressure angle of a cam depends upon
A. Offset between centre lines of cam and follower
B. Lift of follower
C. Angle of ascent
D. All of the above
Answer : D

42. The component of the acceleration, parallel to the velocity of the particle, at the given instant is called
A. Radial component
B. Tangential component
C. Coriolis component
D. None of these
Answer : B

43. The unbalanced primary forces in a reciprocating engine are
A. Balanced completely
B. Balanced partially
C. Balanced by secondary forces
D. Not balanced
Answer : B

44. In order to balance the reciprocating masses,
A. Primary forces and couples must be balanced
B. Secondary forces and couples must be balanced
C. Both (A) and (B)
D. None of these
Answer : C

45. Bifilar suspension method is used to find the
A. Angular acceleration of the body
B. Moment of inertia of the body
C. Periodic time of the body
D. Frequency of vibration of the body
Answer : B

46. A slider moves at a velocity v on a link revolving at ? rad/s. The coriolis component of acceleration is
A. ?v
B. 2?v
C. ?²v
D. 2?v²
Answer : B

47. ________ 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

48. In a four bar chain or quadric cycle chain
A. Each of the four pairs is a turning pair
B. One is a turning pair and three are sliding pairs
C. Two are turning pairs and two are sliding pairs
D. Three are turning pairs and one is a sliding pair
Answer : A

49. In order to give a complete secondary balance of a multi-cylinder inline engine,
A. The algebraic sum of the secondary forces must be equal to zero
B. The algebraic sum of the couples about any point in the plane of the secondary forces must be equal to zero
C. Both (A) and (B)
D. None of these
Answer : C

50. The distance by which the __________ of the D-slide valve overlaps the steam port is called exhaust lap.
A. Inner edge
B. Outer edge
C. Corners
D. None of these
Answer : A