Given, Mass of ball, m=0.2kg Initial speed of ball, u=20m∕s Final speed of ball, v=0ms−1 Time taken, t=0.1s As we know that, F‌‌=ma ⇒‌‌F‌‌=m(‌
v−u
t
) where, F is force. ∴‌‌F‌‌=‌
2
10
(‌
0−20
1
10
) ‌‌=‌
2
10
(−200) ‌‌=−40N Here, -ve sign shows that force is applied in the opposite direction of velocity. These |F|=40N