# Theory of machines – Section 2

41. In a shaper mechanism, the Coriolis component of acceleration does not exist.

A. True
B. False

42. In a gear having involute teeth, the normal to the involute is a tangent to the

A. pitch circle
B. base circle
D. dedendum circle

43. A body is said to be under forced vibrations, when

A. there is a reduction in amplitude after every cycle of vibration
B. no external force acts on a body, after giving it an initial displacement
C. a body vibrates under the influence of the external force
D. none of the above

Correct Answer: A. there is a reduction in amplitude after every cycle of vibration

44. The natural frequency of free longitudinal vibrations is equal to (where m = Mass of the body, s = Stiffness of the body, and δ = Static deflection of the body)

D. any one of these

Correct Answer: D. any one of these

45. The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of the shaft, and tan φ = Coefficient of friction between the shaft and bearing)

Correct Answer: A. r sin φ

46. The maximum and minimum value of the tractive force is given by

47. In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called

A. fluctuation of energy
B. maximum fluctuation of energy
C. coefficient of fluctuation of energy
D. none of these

Correct Answer: A. fluctuation of energy

48. 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

49. The distance between the center of suspension and center of percussion is equal to the equivalent length of a simple pendulum.

A. Agree
B. Disagree