Theory of Machines MCQ Solved Paper for NEET PG

1. A cam with a roller follower would constitute following type of pair
A. Lower pair
B. Higher pair
C. Open pair
D. Close pair
Answer : B

2. 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

3. 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

4. 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

5. The mechanism in which two are turning pairs and two are sliding pairs, is called a
A. Double slider crank chain
B. Elliptical trammel
C. Scotch yoke mechanism
D. All of these
Answer : D

6. The inversion of a mechanism is
A. Changing of a higher pair to a lower pair
B. Turning its upside down
C. Obtained by fixing different links in a kinematic chain
D. Obtained by reversing the input and output motion
Answer : C

7. Rectangular bar in a rectangular hole is the following type of pair
A. Completely constrained motion
B. Partially constrained motion
C. Incompletely constrained motion
D. Freely constrained motion
Answer : A

8. What is the number of instantaneous centres for an eight link mechanism?
A. 15
B. 28
C. 30
D. 8
Answer : B

9. Which of the following statement is correct as regard to the difference between a machine and a structure?
A. The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another
B. The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only
C. A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work
D. All of the above
Answer : D

10. The frictional torque transmitted in a conical pivot bearing, considering uniform pressure, is (where R = Radius of shaft, and ? = Semi-angle of the cone)
A. (1/2) ? W R cosec?
B. (2/3) ? W R cosec?
C. (3/4) ? W R cosec?
D. ? W R cosec?
Answer : B

11. 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

12. 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

13. Which of the following mechanism is an approximate straight line motion mechanism?
A. Watt's mechanism
B. Grasshopper mechanism
C. Robert's mechanism
D. All of these
Answer : D

14. 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

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

16. The example of higher pair is
A. Belt, rope and chain drives
B. Gears, cams
C. Ball and roller bearings
D. All of the above
Answer : D

17. 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

18. If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose mean radius is half the mean radius of the former, then energy stored in the latter at the same speed will be
A. Four times the first one
B. Same as the first one
C. One fourth of the first one
D. One and a half times the first one
Answer : C

19. 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

20. In a disc clutch, if there are n? number of discs on the driving shaft and n? number of discs on the driven shaft, then the number of pairs of contact surfaces will be
A. n? + n?
B. n? + n? + 1
C. n? + n? - 1
D. n? + n? - 2
Answer : C

21. 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

22. In a pantograph, all the pairs are
A. Turning pairs
B. Sliding pairs
C. Spherical pairs
D. Self-closed pairs
Answer : A

23. The centre distance between two meshing involute gears is equal to
A. Sum of base circle radii/cos?
B. Difference of base circle radii/ cos?
C. Sum of pitch circle radii/ cos?
D. Difference of pitch circle radii/ cos?
Answer : A

24. When the addenda on pinion and wheel is such that the path of approach and path of recess are half of their maximum possible values, then the length of the path of contact is given by (where r = Pitch circle radius of pinion, R = Pitch circle radius of wheel, and ? = Pressure angle)
A. [(r² + R²) cos?]/2
B. [(r² + R²) sin?]/2
C. [(r + R) cos?]/2
D. [(r + R) sin?]/2
Answer : D

25. In an open pair, the two elements of a pair
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. Are not held together mechanically
Answer : D

26. A mass of 1 kg is attached to the end of a spring with a stiffness of 0.7 N/mm. The critical damping coefficient of this system is
A. 1.4 N-s/m
B. 18.52 N-s/m
C. 52.92 N-s/m
D. 529.2 N-s/m
Answer : C

27. The transmissibility, for all values of damping factor, will be less than unity, if ?/?_n is
A. Equal to 1
B. Less than 2
C. Equal to 2
D. Greater than 2
Answer : D

28. The velocity of the belt for maximum power is (where m = Mass of the belt in kg per metre length)
A. T/3
B. (T.g)/3
C. ?(T/3m)
D. ?(3m/T)
Answer : C

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

30. 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

31. 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

32. The lower pair is a
A. Open pair
B. Closed pair
C. Sliding pair
D. Point contact pair
Answer : B

33. 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

34. When the elements of a pair are kept in contact by the action of external forces, the pair is said to be a
A. Lower pair
B. Higher pair
C. Self-closed pair
D. Force-closed pair
Answer : D

35. 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

36. 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

37. When the pitching of a ship is __________ the effect of gyroscopic couple acting on it will be to move the ship towards port side.
A. Upward
B. Downward
C. Forward
D. Backward
Answer : B

38. If some links are connected such that motion between them can take place in more than one direction, it is called
A. Incompletely constrained motion
B. Partially constrained motion
C. Completely constrained motion
D. Successfully constrained motion
Answer : A

39. 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

40. An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the
A. Tip of the gear tooth and flank of pinion
B. Tip of the pinion and flank of gear
C. Flanks of both gear and pinion
D. Tip of both gear and pinion
Answer : A

41. When two pulleys of different diameters are connected by means of an open belt, the angle of contact at the ________ pulley must be taken into consideration.
A. Smaller
B. Larger
C. Either A or B
D. None of these
Answer : A

42. The acceleration of a particle moving with simple harmonic motion, at any instant is given by
A. ?x
B. ?²x
C. ?²/x
D. ?³/x
Answer : B

43. 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

44. The maximum efficiency of a screw jack is
A. (1 - sin?)/(1 + sin?)
B. (1 + sin?)/(1 - sin?)
C. (1 - tan?)/(1 + tan?)
D. (1 + tan?)/(1 - tan?)
Answer : A

45. When the primary direct crank of a reciprocating engine makes an angle of ? with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.
A. ?/2
B. ?
C. 2?
D. 4?
Answer : C

46. The pair is known as a higher pair, when the relative motion between the elements of a pair is
A. Turning only
B. Sliding only
C. Rolling only
D. Partly turning and partly sliding
Answer : D

47. The pitching of a ship produces forces on the bearings which act __________ to the motion of the ship.
A. Vertically and parallel
B. Vertically and perpendicular
C. Horizontally and parallel
D. Horizontally and perpendicular
Answer : D

48. The type of pair formed by two elements which are so connected that one is constrained to turn or revolve about a fixed axis of another element is known as
A. Turning pair
B. Rolling pair
C. Sliding pair
D. Spherical pair
Answer : A

49. The minimum periodic time of a compound pendulum is
A. (1/2?). ?(k_G/g)
B. (1/2?). ?(2k_G/g)
C. 2?. ?(k_G/g)
D. 2?. ?(2k_G/g)
Answer : D

50. The product of the diametral pitch and circular pitch is equal to
A. 1
B. 1/?
C. ?
D. 2 ?
Answer : C