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