A ball (mass 0.40 kg) is initially moving to the left at 30 m/s. After hitting the wall, the ball is moving to the right at 20 m/s. What is the impulse of the net force on the ball during its collision with the wall?

A) 20 kg. m/s to the right

B) 20 kg. m/s to the left

C) 4.0 kg. m/s to the right

D) 4.0 kg. m/s to the left

E) none of the above

Option (a)

Explanation:

Impulse is defined as the change in momentum of the body. It is a vector quantity and its SI unit is Kg m/s.

mass of ball, m = 0.4 kg

initial velocity, u = - 30 m/s

Final velocity, v = + 20 m/s

Initial momentum, pi = mass x initial velocity = m u = 0.4 x ( - 30) = - 12 kg m / s

Final momentum, pf = mass x final velocity = mv = 0.4 x 20 = 8 Kg m / s

Change in momentum = final momentum - initial momentum = 8 - ( - 12)

So, impulse = 20 kg m / s right

Option (a) is correct