Theory of Machines MCQ Solved Paper for GMAT

1. 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

2. 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

3. For the same lift and same angle of ascent, a smaller base circle will give
A. A small value of pressure angle
B. A large value of pressure angle
C. There is no such relation with pressure angle
D. Something else
Answer : B

4. The frequency of oscillation of a torsional pendulum is
A. 2?k/r. ?(g/l)
B. r/2?k. ?(l/g)
C. 2?r/k. ?(g/l)
D. r/2?k. ?(g/l)
Answer : D

5. The Klein's diagram is used when
A. Crank has uniform angular velocity
B. Crank has nonuniform angular velocity
C. Crank has uniform angular acceleration
D. Crank has nonuniform angular acceleration
Answer : A

6. Ball and a Socket forms a
A. Turning pair
B. Rolling pair
C. Screw pair
D. Spherical pair
Answer : D

7. For the brake to be self locking, the force P at C shown in the below figure, should
A. Be zero
B. Act in upward direction
C. Act in downward direction
D. None of these
Answer : A

8. 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

9. A spring controlled governor is said to be unstable when the controlling force
A. Increases as the radius of rotation decreases
B. Increases as the radius of rotation increases
C. Decreases as the radius of rotation increases
D. Remains constant for all radii of rotation
Answer : C

10. The cam follower generally used in automobile engines is
A. Knife edge follower
B. Flat faced follower
C. Spherical faced follower
D. Roller follower
Answer : C

11. A disc is a spinning with an angular velocity ? rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ?P = Angular velocity of precession of the axis of spin)
A. (1/2).I?²
B. I?²
C. (1/2). I ? ?_P
D. I ? ?_P
Answer : D

12. When the body is suspended at the point of suspension, its periodic time and frequency will be ________ as compared to the body suspended at the point of percussion.
A. Same
B. Two times
C. Four times
D. None of these
Answer : A

13. The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r? and r? = External and internal radii of collar respectively)
A. (1/2). ? W (r? + r?)
B. (2/3). ? W (r? + r?)
C. (1/2). ? W [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W [(r?³ - r?³)/(r?² - r?²)]
Answer : D

14. The efficiency of a screw jack is maximum, when (where ? = Helix angle, and ? = Angle of friction)
A. ? = 45° + ?/2
B. ? = 45° - ?/2
C. ? = 90° + ?
D. ? = 90° - ?
Answer : B

15. Which of the following mechanism is obtained from lower pair?
A. Gyroscope
B. Pantograph
C. Valve and valve gears
D. All of the above
Answer : D

16. The size of cam depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Pitch curve
Answer : A

17. 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

18. Maximum fluctuation of energy in a flywheel is equal to [where I = Mass moment of inertia of the flywheel, E = Maximum fluctuation of energy, CS = Coefficient of fluctuation of speed, and ? = Mean angular speed = (?? + ??)/2]
A. I.?.(?? - ??)
B. I.?².C_S
C. 2.E.C_S
D. All of these
Answer : D

19. The coriolis component of acceleration is taken into account for
A. Slider crank mechanism
B. Four bar chain mechanism
C. Quick return motion mechanism
D. All of these
Answer : C

20. 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

21. In S.H.M., the velocity vector w.r.t. displacement vector
A. Leads by 90°
B. Lags by 90°
C. Leads by 180°
D. Are in phase
Answer : A

22. Klein's construction can be used to determine acceleration of various parts when the crank is at
A. Inner dead centre
B. Outer dead centre
C. Right angles to the link of the stroke
D. All of the above
Answer : D

23. 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

24. The frictional torque transmitted in a conical pivot bearing with assumption of uniform pressure is __________ as compared to uniform wear.
A. Less
B. More
C. Same
D. None of these
Answer : B

25. In involute gears, the pressure angle is
A. Dependent on the size of teeth
B. Dependent on the size of gears
C. Always constant
D. Always variable
Answer : C

26. The static friction
A. Bears a constant ratio to the normal reaction between the two surfaces
B. Is independent of the area of contact, between the two surfaces
C. Always acts in a direction, opposite to that in which the body tends to move
D. All of the above
Answer : D

27. The axis of precession is __________ to the plane in which the axis of spin is going to rotate.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B

28. The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (?) is equal to
A. 90° and 180°
B. 45° and 225°
C. 180° and 270°
D. 270° and 360°
Answer : B

29. An eccentric sheave pivoted at one point rotates and transmits oscillatory motion to a link whose one end is pivoted and other end is connected to it. This mechanism has
A. 2 links
B. 3 links
C. 4 links
D. 5 links
Answer : C

30. When the radius of rotation of balls __________ as the equilibrium speed increases, the governor is said to be unstable.
A. Remains constant
B. Decreases
C. Increases
D. None of these
Answer : B

31. In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done
A. Because of difficulty in manufacturing cam profile
B. Because of loose contact of follower with cam surface
C. In order to have acceleration in beginning and retardation at the end of stroke within the finite limits
D. Because the uniform velocity motion is a partial parabolic motion
Answer : C

32. 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

33. 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

34. Sense of tangential acceleration of a link
A. Is same as that of velocity
B. Is opposite to that of velocity
C. Could be either same or opposite to velocity
D. Is perpendicular to that of velocity
Answer : C

35. When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a
A. Lower pair
B. Higher pair
C. Self-closed pair
D. Force-closed pair
Answer : A

36. In a reciprocating engine, usually __________ of the reciprocating masses are balanced.
A. One-half
B. Two-third
C. Three-fourth
D. Whole
Answer : B

37. The motion of a shaft in a circular hole is an example of
A. Completely constrained motion
B. Incompletely constrained motion
C. Successfully constrained motion
D. None of these
Answer : B

38. The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
A. 0° and 90°
B. 0° and 180°
C. 90° and 180°
D. 180° and 360°
Answer : B

39. Cam size depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Outer circle
Answer : A

40. The condition for correct steering of a Davis steering gear is (where ? = Angle of inclination of the links to the vertical)
A. sin? = b/c
B. cos? = c/b
C. tan? = c/2b
D. cot? = c/2b
Answer : C

41. 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
Answe : B

42. The number of centers in a crank driven slider crank mechanism is
A. 0
B. 2
C. 4
D. 6
Answer : B

43. Which of the following is used to control the speed variations of the engine caused by the fluctuations of the engine turning moment?
A. D-slide valve
B. Governor
C. Flywheel
D. Meyer's expansion valve
Answer : C

44. A Hartnell governor is a
A. Dead weight governor
B. Pendulum type governor
C. Spring loaded governor
D. Inertia governor
Answer : C

45. A kinematic chain requires at least
A. 2 links and 3 turning pairs
B. 3 links and 4 turning pairs
C. 4 links and 4 turning pairs
D. 5 links and 4 turning pairs
Answer : C

46. Which of the following is a pendulum type governor?
A. Watt governor
B. Porter governor
C. Hartnell governor
D. None of these
Answer : A

47. The primary unbalanced force is maximum _________ in one revolution of the crank.
A. Twice
B. Four times
C. Eight times
D. Sixteen times
Answer : A

48. 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

49. Idler pulley is used
A. For changing the direction of motion of the belt
B. For applying tension
C. For increasing velocity ratio
D. All of the above
Answer : B

50. In a locomotive, the maximum magnitude of the unbalanced force along the perpendicular to the line of stroke, is known as
A. Tractive force
B. Swaying couple
C. Hammer blow
D. None of these
Answer : C