Question

A penalty shot requires a football player to hit a stationary ball of mass 500 g. A football player weighing 60000 g hits the ball at 50 m/s towards the goal post and slows down to 40 m/s. Calculate the change in momentum of the ball.​

Answer 1

Given:

A penalty shot requires a football player to hit a stationary ball of mass 500 g. A football player weighing 60000 g hits the ball at 50 m/s towards the goal post and slows down to 40 m/s.

To find:

Change in momentum of the ball.

Calculation:

According to Conservation of Momentum , the change in momentum of the player will be equal and opposite to the change in momentum of the ball.

$\therefore \: \Delta P_{(player)} = - \Delta P_{(ball)}$

$= > \: m_{(player)} (v - u)= - \Delta P_{(ball)}$

$= > \: m_{(player)} (u - v)= \Delta P_{(ball)}$

$= > \: \Delta P_{(ball)} = (\dfrac{60000}{1000} ) \times (50 - 40)$

$= > \: \Delta P_{(ball)} = 60 \times (50 - 40)$

$= > \: \Delta P_{(ball)} = 60 \times 10$

$= > \: \Delta P_{(ball)} = 600 \: kgm {s}^{ - 1}$

So, final answer is:

$\boxed{ \bf{\: \Delta P_{(ball)} = 600 \: kgm {s}^{ - 1} }}$