I don't understand physics!!?

Question

A barefoot field-goal kicker imparts a speed of 16m/s to a football initially at rest. If the football has a mass of .58kg, & the time of contact with the ball is .013s, what is the force exerted by teh ball on the kicker's foot?

Does anyone understand this question at all?? Cause I don't...

Answer 1

He's exerting 12.2 Newtons of force. Duh.

Answer 2

Force = mass x acceleration = mass (change in velocity / time)

= 0.58 kg(16 m/s / 0.013 s) = 714 N

Answer 3

Change in momentum of the ball = Mb(Vf - Vo)

where

Mb = mass of the ball = 0.58 (given)

Vf = final velocity of the ball = 16 m/sec.

Vo = initial velocity of the ball = 0 (ball is at rest initially)

Therefore, substituting appropriate values,

Change in momentum = 0.58(16 - 0) = 9.28

NOTE that the change in momentum = F(delta T)

where

F = force imparted on the body

delta T = time that source of force is in contact with the body = 0.013

Thus being said,

F(0.013) = 9.28

F = 713.85 Newtons