A football of mass 5 kg moving with a velocity of 10 m/s hits a pole and, the ball bounces back with a velocity of 5m/s. Find the change in momentum and the force exerted on the ball, if the force acts for 0.02s.

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A rubber ball of mass 250 g hits a wall normally with a velocity 10ms−1 and bounces back with a velocity of 8ms−1. The impluse is _______N s.

The correct option is B −4.5The ball initially has 10 m/s in the positive x - direction and 8 m/s in the negative x-directionv =−8m/su=10m/sImpulse is the change in momentum=mv−muI=0.25×(−8−10)NsI=−4.5Ns

A rubber ball of mass 250 g hits a wall normally with a velocity $10 m s^{- 1}$ and bounces back with a velocity of $8 m s^{- 1}$ . The impluse is _______N s.

The correct option is B $- 4.5$
The ball initially has 10 m/s in the positive x - direction and 8 m/s in the negative x-direction
v $= - 8 m / s$
$u = 10 m / s$
Impulse is the change in momentum $= m v - m u$
$I = 0.25 \times (- 8 - 10) N s$
$I = - 4.5 N s$