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

1. A spring controlled governor is found unstable. It can be made stable by
A. Increasing the spring stiffness
B. Decreasing the spring stiffness
C. Increasing the ball mass
D. Decreasing the ball mass
Answer : B

2. Higher pairs are those which have
A. Point or line contact between the two elements when in motion
B. Surface contact between the two elements when in motion
C. Elements of pairs not held together mechanically
D. Two elements that permit relative motion
Answer : A

3. Angular acceleration of a link can be determined by dividing the
A. Centripetal component of acceleration with length of link
B. Tangential component of acceleration with length of link
C. Resultant acceleration with length of link
D. All of the above
Answer : B

4. 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

5. The velocity of sliding __________ the distance of the point of contact from the pitch point.
A. Is directly proportional to
B. Is inversely proportional to
C. Is equal to cos ? multiplied by
D. Does not depend upon
Answer : A

6. If two moving elements have surface contact in motion, such pair is known as
A. Sliding pair
B. Rolling pair
C. Surface pair
D. Higher pair
Answer : D

7. The velocity of the rubbing surface __________ with the distance from the axis of the bearing.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A

8. Peaucelliers mechanism has
A. Eight links
B. Six links
C. Four links
D. Twelve links
Answer : A

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

10. The gear train usually employed in clocks is a
A. Simple gear train
B. Reverted gear train
C. Sun and planet gear
D. Differential gear
Answer : B

11. 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

12. When a point at the end of a link moves with constant angular velocity, its acceleration will have
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : A

13. In full depth involute system, the smallest number of teeth in a pinion which meshes with rack without interference is
A. 12
B. 16
C. 25
D. 32
Answer : D

14. In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to
A. Reduce vibration
B. Reduce slip
C. Ensure uniform loading
D. Ensure proper alignment
Answer : C

15. The centre of gravity of a coupler link in a four bar mechanism will experience
A. No acceleration
B. Only linear acceleration
C. Only angular acceleration
D. Both linear and angular acceleration
Answer : D

16. Which of the following is a higher pair?
A. Belt and pulley
B. Turning pair
C. Screw pair
D. Sliding pair
Answer : A

17. The swaying couple is due to the
A. Primary unbalanced force
B. Secondary unbalanced force
C. Two cylinders of locomotive
D. Partial balancing
Answer : A

18. The number of links and instantaneous centers in a reciprocating engine mechanism are
A. 4, 4
B. 4, 5
C. 5, 4
D. 4, 6
Answer : D

19. The total number of instantaneous centres for a mechanism consisting of n links are
A. n/2
B. n
C. n - 1
D. n(n - 1)/2
Answer : D

20. When the axes of the first and last wheels are coaxial, then the train is known as
A. Simple train of wheels
B. Compound train of wheels
C. Reverted gear train
D. Epicyclic gear train
Answer : C

21. In a screw jack, the effort required to lower the load W is given by
A. P = W tan(? - ?)
B. P = W tan(? + ?)
C. P = W tan(? - ?)
D. P = W cos(? + ?)
Answer : C

22. When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as
A. Simple pendulum
B. Compound pendulum
C. Torsional pendulum
D. Second's pendulum
Answer : B

23. Which one of the following is an exact straight line mechanism using lower pairs?
A. Watts mechanism
B. Grasshopper mechanism
C. Roberts mechanism
D. Peaucelliers mechanism
Answer : D

24. When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a
A. D-slide valve
B. Governor
C. Meyer's expansion valve
D. Flywheel
Answer : B

25. Shaft revolving in a bearing is the following type of pair
A. Lower pair
B. Higher pair
C. Spherical pair
D. Cylindrical pair
Answer : A

26. 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

27. The example of rolling pair is
A. Bolt and nut
B. Lead screw of a lathe
C. Ball and socket joint
D. Ball bearing and roller bearing
Answer : D

28. Tangential acceleration direction is
A. Along the angular velocity
B. Opposite to angular velocity
C. May be any one of these
D. Perpendicular to angular velocity
Answer : C

29. Transmission angle is the angle between
A. Input link and coupler
B. Input link and fixed link
C. Output link and coupler
D. Output link and fixed link
Answer : C

30. In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as
A. Critical damping ratio
B. Damping factor
C. Logarithmic decrement
D. Magnification factor
Answer : D

31. 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

32. The cam and follower is an example of
A. Sliding pair
B. Rolling pair
C. Lower pair
D. Higher pair
Answer : D

33. A circle passing through the pitch point with its center at the center of cam axis is known as
A. Pitch circle
B. Base circle
C. Prime circle
D. Outer circle
Answer : C

34. If ?/?_n is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
A. 0°
B. 90°
C. 180°
D. 360°
Answer : C

35. In the two rotor system as shown in the below figure (I? < I?), a node of vibration is situated
A. Between I?, and I? but nearer I?
B. Between I?, and I? but nearer to I?
C. Exactly in the middle of the shaft
D. Nearer to I? but outside
Answer : B

36. At the nodal point in a shaft, the amplitude for torsional vibration will be
A. Minimum
B. Maximum
C. Zero
D. Infinity
Answer : C

37. When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be
A. Stable
B. Unstable
C. Isochronous
D. Hunt
Answer : D

38. Creep in belt drive is due to
A. Weak material of the belt
B. Weak material of the pulley
C. Uneven extensions and contractions of the belt when it passes from tight side to slack side
D. Expansion of the belt
Answer : C

39. 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

40. To obviate axial thrust, following gear drive is used
A. Double helical gears having opposite teeth
B. Double helical gears having identical teeth
C. Single helical gear in which one of the teeth of helix angle a is more
D. Mutter gears
Answer : A

41. The power transmitted by a belt is maximum when the maximum tension in the belt is _________ of centrifugal tension.
A. One-third
B. Two-third
C. Double
D. Three times
Answer : D

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

4. To connect two parallel and coplanar shafts the following type of gearing is used
A. Spur gear
B. Bevel gear
C. Spiral gear
D. None of the above
Answer : A

44. The load cup of a screw jack is made separate from the head of the spindle to
A. Enhance the load carrying capacity of the jack
B. Reduce the effort needed for lifting the working load
C. Reduce the value of frictional torque required to be countered for lifting the load
D. Prevent the rotation of load being lifted
Answer : D

45. 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

46. In a spring controlled governor, when the controlling force ________ as the radius of rotation increases, it is said to be a stable governor.
A. Remains constant
B. Decreases
C. Increases
D. None of these
Answer : C

47. The frequency of oscillation at compared to earth will be
A. 6 times more
B. 6 times less
C. 2.44 times more
D. 2.44 times less
Answer : D

48. A pantograph is a mechanism with
A. Lower pairs
B. Higher pairs
C. Rolling pairs
D. Turning pairs
Answer : A

49. 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

50. The velocity of a body moving with simple harmonic motion is __________ at the mean position.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : C