JAMB Physics Past Questions & Answers - Page 73

361.

A body of mass 100g moving with a velocity of 10ms-1 collides with a wall. If after collision it moves with a velocity of 2.0ms−1 in the opposite direction, calculate the change in momentum.

A.

0.8Ns

B.

1.2Ns

C.

12.0Ns

D.

80.0Ns

Correct answer is B

Momentum = Mass x Velocity
Change in Momentum = Mass x (change in velocity)
Change in Momentum = Mass x (v - u)
Mass = 100g = 0.1kg
U = 2ms\(^{-1}\)
V = 10ms\(^{-1}\)
Change in momentum = m (v − u)
= 0.1 (2 -(- 10))
= 0.1 (12)
= 1.2Ns

362.

The force between the molecules of a liquid in contact with that of a solid is?

A.

Adhesive

B.

Cohesive

C.

Magnetic

D.

Repulsive

Correct answer is A

The term Adhesive forces refers to the attractive forces between unlike substance

363.

A ball of mass 800g moving horizontally with a speed of 5m/s hits a vertical wall and rebounds with the same speed. The impulse experienced by the ball is?

A.

0kgm

B.

2kgm/s

C.

4kgm/s

D.

8kgm/s

Correct answer is D

Initial momentum = (0.8) × (5)

 = 4.0kgms\(^{-1}\)

  Final momentum

  = (0.8) × (– 5)

 = – 4.0kgms\(^{-1}\)

  Impulse on ball

  = Change in momentum

 = 4.0 – (– 4.0)

  = 8.0.0kgms\(^{-1}\)

364.

When an atom loses or gain a charge it becomes

A.

An electron

B.

An ion

C.

A neutron

D.

A proton

Correct answer is B

If an atom gains or loses an electron, it becomes an ion. An atom that gains a negative electron, it becomes a negative ion. If it loses an electron it becomes a positive ion