1000+ Theory of Machines Multiple Choice Question Answer [Solved]

1. In under damped vibrating system, the amplitude of vibration
A. Decreases linearly with time
B. Increases linearly with time
C. Decreases exponentially with time
D. Increases exponentially with time
Answer : C

2. 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

3. 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

4. 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

5. The indicator using Watt mechanism is known as
A. Thompson indicator
B. Richard indicator
C. Simplex indicator
D. Thomson indicator
Answer : B

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

7. Which one of the following can completely balance several masses revolving in different planes on a shaft?
A. A single mass in different planes
B. Two masses in any two planes
C. A single mass in one of the planes of the revolving masses
D. Two equal masses in any two planes
Answer : B

8. A circular bar moving in a round hole is an example of
A. Incompletely constrained motion
B. Partially constrained motion
C. Completely constrained motion
D. Successfully constrained motion
Answer : A

9. A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
A. a is +ve and b = 0
B. a = 0 and b is +ve
C. a is +ve and b is -ve
D. a is +ve and b is also +ve
Answer : A

10. The flank of the tooth is the surface of the tooth __________ the pitch surface.
A. Above
B. Below
C. At
D. None of these
Answer : B

11. For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimed stroke respectively, is
A. Maximum and zero
B. Zero and maximum
C. Minimum and maximum
D. Zero and minimum
Answer : A

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

13. Oldham's coupling is the
A. Second inversion of double slider crank chain
B. Third inversion of double slider crank chain
C. Second inversion of single slider crank chain
D. Third inversion of slider crank chain
Answer : B

14. 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

15. The equation of free vibrations of a system is (d²x/dt²) +36 ?²x, its natural frequency is
A. 3 Hz
B. 3? Hz
C. 6 Hz
D. 6? Hz
Answer : A

16. 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

17. 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

18. The frictional torque transmitted in a flat pivot bearing, considering uniform pressure, is (where ? = Coefficient of friction, W = Load over the bearing, and R = Radius of bearing surface)
A. (1/2) ? W R
B. (2/3) ? W R
C. (3/4) ? W R
D. ? W R
Answer : B

19. With usual notations for different parameters involved, the maximum fluctuations of energy for a flywheel is given by
A. 2EC_S
B. EC_S/2
C. 2EC_S²
D. 2E²C_S
Answer : A

20. 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

21. In higher pair, the relative motion is
A. Purely turning
B. Purely sliding
C. Purely rotary
D. Combination of sliding and turning
Answer : D

22. 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

23. 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

24. A point on a link connecting double slider crank chain traces a
A. Ellipse
B. Circle
C. Parabola
D. Hyperbola
Answer : A

25. 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

26. A point on a connecting link (excluding end points) of a double slider crank mechanism traces a
A. Straight line path
B. Hyperbolic path
C. Parabolic path
D. Elliptical path
Answer : D

27. 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

28. 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

29. 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

30. The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (?) is equal to
A. 0° and 90°
B. 90° and 180°
C. 135° and 315°
D. 270° and 360°
Answer : B

31. The frequency of oscillation of a compound pendulum is
A. 2?. ?[gh/(k_G² + h²)]
B. 2?. ?[(k_G² + h²)/gh]
C. (1/2?). ?[gh/(k_G² + h²)]
D. (1/2?). ?[(k_G² + h²)/gh]
Answer : C

32. 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

33. The radial distance of a tooth from the pitch circle to the bottom of the tooth is called
A. Dedendum
B. Addendum
C. Clearance
D. Working depth
Answer : A

34. 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

35. 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

36. 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

37. The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m). (dx/dt) + (s/m). x = 0 If the roots of this equation are real, then the system will be
A. Over-damped
B. Under damped
C. Critically damped
D. Without vibrations
Answer : A

38. The dedendum circle diameter is equal to (where, ? = Pressure angle)
A. Pitch circle dia. × cos?
B. Addendum circle dia. × cos?
C. Clearance circle dia. × cos?
D. Pitch circle dia. × sin?
Answer : A

39. 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

40. The velocity of a particle moving with simple harmonic motion, at any instant is given by (where ? = Displacement of the particle from mean position)
A. ? ?(x² - r²)
B. ? ?(r² - x²)
C. ?² ?(x² - r²)
D. ?² ?(r² - x²)
Answer : B

41. Kinematic 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 : D

42. The example of lower pair is
A. Shaft revolving in a bearing
B. Straight line motion mechanisms
C. Automobile steering gear
D. All of the above
Answer : D

43. 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 distance between fixed pivots of crank and followers is
A. 95 mm
B. Slightly less than 95 mm
C. Slightly more than 95 mm
D. 45 mm
Answer : B

44. The primary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ? = Angular speed of crank, r = Radius of crank, ? = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)
A. m.?².r sin?
B. m.?².r cos?
C. m.?².r (sin 2?/n)
D. m.?².r (cos 2?/n)
Answer : B

45. 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

46. 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

47. The coriolis component of acceleration exists whenever a point moves along a path that has
A. Linear displacement
B. Rotational motion
C. Gravitational acceleration
D. Tangential acceleration
Answer : B

48. 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

49. 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

50. When brakes are applied to all the four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be
A. Maximum
B. Minimum
C. Zero
D. None of these
Answer : B