Aball (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