Theory of Machines MCQ Solved Paper for NEET

1. Longitudinal vibrations are said to occur when the particles of a body moves
A. Perpendicular to its axis
B. Parallel to its axis
C. In a circle about its axis
D. None of these
Answer : B

2. 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

3. 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

4. The type of gears used to connect two non parallel and non intersecting shafts is
A. Spur gear
B. Helical gear
C. Bevel gear
D. Spiral gear
Answer : D

5. Length of arc of contact is given by
A. Arc of approach - Arc of recess
B. Arc of approach + Arc of recess
C. Arc of approach / Arc of recess
D. Arc of approach × Arc of recess
Answer : B

6. 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. The acceleration of the piston P with respect to the crankpin C is given by
A. ?² × NO
B. ?² × CO
C. ?² × CN
D. ?² × QN
Answer : C

7. Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?
A. Theory of machines
B. Applied mechanics
C. Mechanisms
D. Kinetics
Answer : A

8. In gears, interference takes place when
A. The tip of a tooth of a mating gear digs into the portion between base and root circles
B. Gears do not move smoothly in the absence of lubrication
C. Pitch of the gears is not same
D. Gear teeth are undercut
Answer : A

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

10. 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

11. Cross head and guides form a
A. Lower pair
B. Higher pair
C. Turning pair
D. Sliding pair
Answer : D

12. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform pressure, is
A. (1/2). ? W cosec? (r? + r?)
B. (2/3). ? W cosec? (r? + r?)
C. (1/2). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
Answer : D

13. Which is the false statement about the properties of instantaneous centre?
A. At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered
B. The two rigid links have no linear velocities relative to each other at the instantaneous centre
C. The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link
D. The double centre can be denoted either by O2 or O12, but proper selection should be made
Answer : D

14. 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

15. 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

16. 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

17. 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

18. 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

19. V-belts are usually used for
A. Long drives
B. Short drives
C. Long and short drives
D. None of these
Answer : B

20. The advantage of the piston valve over the slide valve is that in the former case
A. Wear is less
B. Power absorbed is less
C. Both wear and power absorbed are low
D. The pressure developed being high provides tight sealing
Answer : C

21. 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

22. The factor which affects the critical speed of a shaft is
A. Diameter of disc
B. Span of shaft
C. Eccentricity
D. All of these
Answer : D

23. 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

24. The magnitude of linear velocity of a point B on a link AB relative to point A is (Where ? = Angular velocity of the link AB)
A. ? × AB
B. ? × (AB)²
C. ?² × AB
D. (? × AB)²
Answer : A

25. The D-slide valve is also known as
A. Inside admission valve
B. Outside admission valve
C. Piston slide valve
D. None of these
Answer : B

26. Which gear train is used for higher velocity ratios in a small space?
A. Simple gear train
B. Compound gear train
C. Reverted gear train
D. Epicyclic gear train
Answer : D

27. The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as
A. Completely constrained motion
B. Incompletely constrained motion
C. Successfully constrained motion
D. None of these
Answer : A

28. 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

29. If the number of links in a mechanism is equal to l, then the numbers of possible inversions are equal to
A. l - 2
B. l - 1
C. l
D. l + 1
Answer : C

30. The unbalanced force due to reciprocating masses
A. Varies in magnitude but constant in direction
B. Varies in direction but constant in magnitude
C. Varies in magnitude and direction both
D. Constant in magnitude and direction both
Answer : A

31. Which of the following would constitute a link?
A. Piston, piston rod and cross head
B. Piston and piston rod
C. Piston rod and cross head
D. Piston, crank pin and crank shaft
Answer : A

32. 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

33. 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

34. The Klein's method of construction for reciprocating engine mechanism
A. Is based on acceleration diagram
B. Is a simplified form of instantaneous center method
C. Utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine
D. Enables determination of Carioles component
Answer : C

35. In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The minimum length of the coupler will be
A. 45 mm
B. Slightly less than 45 mm
C. Slightly more than 45 mm
D. 95 mm
Answer : C

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

37. 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

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

39. Which of the following statement is wrong?
A. A round bar in a round hole form a turning pair
B. A square bar in a square hole form a sliding pair
C. A vertical shaft in a foot step bearing forms a successful constraint
D. All of the above
Answer : C

40. 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

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

42. If the opposite links of a four bar linkage are equal, the links will always form a
A. Triangle
B. Rectangle
C. Parallelogram
D. Pentagon
Answer : C

43. A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the
A. Magnitude of the forces on journal
B. Angular velocity of journal
C. Clearance between journal and bearing
D. Radius of journal
Answer : D

44. 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

45. The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft, and I = Mass moment 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

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

47. The fundamental equation for correct steering is (where ? and ? = Angle through which the axis of the outer wheel and inner wheel turns respectively, c = Distance between the pivots of the front axles, and d = Wheel base)
A. sin? + sin? = b/c
B. cos? - sin? = c/b
C. cot? - cot? = c/b
D. tan? + cot? = b/c
Answer : C

48. Lower 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 : B

49. 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

50. 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