A ball is moving in air at `15 m*s^(-1)`. The ball is hit with a bat and it attains a velocity of `20 m*s^(-1)` in the opposite direction . If its kinetic energy changes by 8.75 J , what is the change in its momentum ?

Explanation

Change in kinetic energy of the ball,
`Delta K =1/2 m(v_2^2-v_1^2) `
or, `8. 75 =1/2 m(20^2-15^2) or, m=(2xx8.75)/(35xx5) =0.1 kg`
`therefore` The change in momentum of the ball
`=m [v_1-(-v_2)] =m (v_1+v_2) `
` =0.1 (15+20)=3.5 kg *m*s^(-1)`.