Question

a football of mass 0.38 kg is traveling towards a boy at 2.8ms-1. the boy kicks the ball with a force of 21N, reversing its direction. if the time of imapct between the football and boy’s foot is 250ms. what is the new speed of trhe ball?

Answer 1

Final speed in reverse direction will be 11 m/s

Step-by-step explanation:

As per impulse momentum theorem we know that

Change in momentum of the object is product of force and time

so we have

`P_f - P_i = F\Delta t`

now we have

`P_f = mv_f`

`P_i = mv_i`

`\Delta t = 250 ms`

F = 21 N

now we have

`0.38(v_f) - 0.38(-2.8) = 21(250* 10^(-3))`

`v_f = 13.82 - 2.8`

`v_f = 11 m/s`