# Engineering Mechanics – Section 1

41. A resultant force is a single force which produces the same effect as produced by all the given forces acting on a body.

A. True
B. False

42. When a rigid body is suspended vertically, and it oscillates with a small amplitude under the action of the force of gravity, the body is known as

A. simple pendulum
B. compound pendulum
C. torsional pendulum
D. second’s pendulum

43. Moment of inertia of a hollow circular section, as shown in the below figure about X-axis, is  44. If two blocks of equal mass are attached to the two ends of a light string and one of the blocks is placed over a smooth horizontal plane while the other is hung freely after passing over a smooth pulley, then the two blocks will have some motion.

A. Agree
B. Disagree

45. During elastic impact, the relative velocity of the two bodies after impact is __________ the relative velocity of the two bodies before impact.

A. equal to
B. equal and opposite to
C. less than
D. greater than

Correct Answer: B. equal and opposite to

46. Work done is said to be zero, when

A. some force acts on a body, but displacement is zero
B. no force acts on a body but some displacement takes place
C. either (a) or (b)
D. none of the above

Correct Answer: C. either (a) or (b)

47. The force which acts along the radius of a circle and directed away from the center of the circle is called centrifugal force.

A. Agree
B. Disagree

48. One watt is equal to

A. 0.1 joule/s
B. 1 joule/s
C. 10 joules/s
D. 100 joules/s

49. two like parallel forces are acting at a distance of 24 mm apart and their resultant is 20 N. It the line of action of the resultant is 6 mm from any given force, the two forces are

A. 15 N and 5 N
B. 20 N and 5 N
C. 15 N and 15 N
D. none of these

Correct Answer: A. 15 N and 5 N

50. If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies, the momentum of the body having mass m1 is __________ the momentum of the body having mass m2
.
A. equal to
B. less than
C. greater than