# Engineering Mechanics – Section 1

1. According to the principle of conservation of energy, the total momentum of a system of masses in any direction remains constant unless acted upon by an external force in that direction.

A. True
B. False

2. The friction experienced by a body, when in motion, is known as

A. rolling friction
B. dynamic friction
C. limiting friction
D. static friction

3. Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the ball with velocity v is made to strike the second ball. Both the balls after impact will move with a velocity

A. v
B. v/2
C. v/4
D. v/8

4. The term ‘force’ may be defined as an agent which produces or tends to produce, destroys or tends to destroy motion.

A. Agree
B. Disagree

5. The coefficient of restitution for elastic bodies is one.

A. Correct
B. Incorrect

The Coefficient of restitution for elastic bodies is 0 – 1.
The coefficient of restitution for perfect elastic bodies is 1.

6. The velocity ratio in case of an inclined plane inclined at angle θ to the horizontal and weight being pulled up the inclined plane by vertical effort is

A. sin θ
B. cos θ
C. tan θ
D. cosec θ

7. The range of projectile on a downward inclined plane is __________ the range on the upward inclined plane for the same velocity of projection and angle of projection.

A. less than
B. more than
C. equal to

8. The angle of inclination of a vehicle when moving along a circular path __________ upon its mass.

A. depends
B. does not depend

Correct Answer: B. does not depend

9. A body of weight W is required to move up on a rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by(where μ = tanφ = Coefficient of friction between the plane and the body.)

A. P = W tanα
B. P = W tan(α + φ)
C. P = W (sinα + μcosα)
D. P = W (cosα + μsinα)

Correct Answer: C. P = W (sinα + μcosα)

10. If the resultant of two equal forces have the same magnitude as either of the forces, then the angle between the two forces is

A. 30°
B. 60°
C. 90°
D. 120°