Theory of Machines 1000+ MCQ with answer for CAT

1. Which type of gear train is used in clock mechanism to join hour hand and minute hand?
A. Simple gear train
B. Compound gear train
C. Reverted gear train
D. Epicyclic gear train
Answer : D

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

3. A system in dynamic balance implies that
A. The system is critically damped
B. There is no critical speed in the system
C. The system is also statically balanced
D. There will absolutely no wear of bearings
Answer : C

4. The absolute acceleration of any point P in a link about center of rotation O is
A. Along PO
B. Perpendicular to PO
C. At 45° to PO
D. None of the above
Answer : D

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

6. When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will
A. Return to equilibrium position without oscillation
B. Oscillate with increasing time period
C. Oscillate with decreasing amplitude
D. Oscillate with constant amplitude
Answer : B

7. 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

8. Pulley in a belt drive acts as
A. Cylindrical pair
B. Turning pair
C. Rolling pair
D. Sliding pair
Answer : C

9. The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where ? = Coefficient of friction, W=Load over the bearing, R=Radius of bearing)
A. ?wr
B. ¾?WR
C. (2/3) ?WR
D. ½?WR
Answer : D

10. 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

11. The ratio of maximum fluctuation of speed to the mean speed is called
A. Fluctuation of speed
B. Maximum fluctuation of speed
C. Coefficient of fluctuation of speed
D. None of these
Answer : C

12. The balancing of a rigid rotor can be achieved by appropriately placing balancing masses in
A. A single plane
B. Two planes
C. Three planes
D. Four planes
Answer : B

13. The working depth of a gear is the radial distance from the
A. Pitch circle to the bottom of a tooth
B. Pitch circle to the top of a tooth
C. Top of a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : D

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

15. 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

16. When the nature of contact between the elements of a pair is such that one element can turn about the other by screw threads, the pair is known as a
A. Screw pair
B. Spherical pair
C. Turning pair
D. Sliding pair
Answer : A

17. Which of the following disciplines provides study of relative motion between the parts of a machine?
A. Theory of machines
B. Applied mechanics
C. Mechanisms
D. Kinematics
Answer : D

18. In a simple train of wheels, the velocity ratio __________ the intermediate wheels.
A. Depends upon
B. Is independent of
C. Either A or B
D. None of these
Answer : B

19. The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ? = Angular speed of crank, r = Radius of crank, and ? = Angle of inclination of crank to the line of stroke)
A. m.?².r cos?
B. c.m.?².r sin?
C. (1 - c).m.?².r (cos? - sin?)
D. m.?².r (cos? - sin?)
Answer : C

20. Pitch point of a cam is
A. A point on the pitch curve having minimum pressure angle
B. A point on the pitch curve having maximum pressure angle
C. Any point on the pitch curve
D. Any point on the pitch circle
Answer : B

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

22. The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft, and I = Mass momet of inertia of the disc attached at the end of a shaft)
A. 2?. ?(q/I)
B. 2? qI
C. (1/2?). ?(q/I)
D. 1/2?
Answer : C

23. Hammer blow
A. Is the maximum horizontal unbalanced force caused by the mass provided to balance the reciprocating masses.
B. Is the maximum vertical unbalanced force caused by the mass added to balance the reciprocating masses
C. Varies as the square root of the speed
D. Varies inversely with the square of the speed
Answer : B

24. In under damped vibrating system, if x? and x? are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to
A. x?/x?
B. log(x?/x?)
C. log_e(x?/x?)
D. log(x?.x?)
Answer : B

25. 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

26. In a band and block brake, the ratio of tensions on tight side and slack side of the band is (where ? = Coefficient of friction between the blocks and the drum, ? = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
A. T?/T? = ?. ?. n
B. T?/T? = [(1 - ? tan?)/(1 + ? tan?)]n
C. T?/T? = (? ?)n
D. T?/T? = [(1 + ? tan?)/(1 - ? tan?)]n
Answer : D

27. 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

28. A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is
A. 5,367 r.p.m.
B. 6,000 r.p.m.
C. 9,360 r.p.m.
D. 12,000 r.p.m.
Answer : A

29. The coriolis component of acceleration depends upon
A. Velocity of slider
B. Angular velocity of the link
C. Both (A) and (B)
D. None of these
Answer : C

30. 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

31. The displacement of the reciprocating roller follower, when it has contact with the straight flanks of the tangent cam, is given by (where r? = Minimum radius of the cam, r? = Radius of the roller follower, and ? = Angle turned by the cam from the beginning of the follower displacement)
A. (r? - r?) (1 - cos?)
B. (r? + r?) (1 + cos?)
C. (r? - r?) [(1 - cos?)/cos ?]
D. (r? + r?) [(1 - cos?)/cos ?]
Answer : D

32. A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 10 rad/s. When the shaft is rotated at 300 r.p.m., it will whirl with a radius of
A. 2 mm
B. 2.22 mm
C. 2.50 mm
D. 3.0 mm
Answer : B

33. Which of the following is an example of sliding pair?
A. Piston and cylinder of a reciprocating steam engine
B. Shaft with collars at both ends fitted into a circular hole
C. Lead screw of a lathe with nut
D. Ball and a socket joint
Answer : A

34. 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

35. 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

36. In a hydrodynamic journal bearing, there is
A. A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
B. A thick film of lubricant between the journal and the bearing
C. No lubricant between the journal and the bearing
D. A forced lubricant between the journal and the bearing
Answer : B

37. 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

38. Open 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 : C

39. 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

41. 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

42. Which gear is used for connecting two coplanar and intersecting shafts?
A. Spur gear
B. Helical gear
C. Bevel gear
D. None of the above
Answer : C

43. The approximate straight line mechanism is a
A. Four bar linkage
B. 6 bar linkage
C. 8 bar linkage
D. 3 bar linkage
Answer : A

44. In a coupling rod of a locomotive, each of the four pairs is a ________ pair.
A. Sliding
B. Turning
C. Rolling
D. Screw
Answer : B

45. 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

46. In automobiles the power is transmitted from gear box to differential through
A. Bevel gear
B. Universal joint
C. Hooke's joint
D. Knuckle joint
Answer : C

47. Pitch point on a cam is
A. Any point on pitch curve
B. The point on cam pitch curve having the maximum pressure angle
C. Any point on pitch circle
D. The point on cam pitch curve having the minimum pressure angle
Answer : B

48. In the below figure, PC is the connecting rod and OC is the crank making an angle ? with the line of stroke PO and rotates with uniform angular velocity at ? rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO, if N coincides with O, then
A. Acceleration and velocity of the piston P is zero
B. Acceleration and velocity of the piston P is maximum
C. Acceleration of the piston P is zero and its velocity is maximum
D. Acceleration of the piston P is maximum and its velocity is zero
Answer : C

49. If the pressure angle is __________, a reciprocating follower will jam in its bearings.
A. Small
B. Too small
C. Large
D. Too large
Answer : D

50. The height of a Watt's governor (in metres) is equal to (where N = Speed of the arm and ball about the spindle axis)
A. 8.95/N²
B. 89.5/N²
C. 895/N²
D. 8950/N²
Answer : C