1. A0_50 kg football is thrown with a velocity of 15 m/s to the right. A sta-

tionary rocciver catches the ball and brings it to rest in 0.020 s. What is

the force exerted on the receiver?

Answer: 375 Newton

Explanation:

Initial velocity = 15 m/s

Final velocity = 0 m/s

Mass of football = 0.50kg

Time taken = 0.020Seconds

Force = (Change in momentum / Time taken)

Since, change in momentum = Mass (final velocity - initial velocity)

Change in momentum = 0.50 x (0 - 15)

= 0.50 (-15)

= - 7.5kgm/s

Then, put - 7.5kgm/s in the equation of force

i. e Force = (Change in momentum / Time taken)

Force = ( - 7.5kgm/s / 0.020 Seconds)

Force = 375 Newton (note that the negative sign does not affect the value of force)

Thus, 375 Newton of force was exerted on the receiver