posted by marissa
a football punter accelerates from rest to a speed of 8 m/s during the time in which his toe is in contact with the ball (about 0.21 s). If the football has a mass of 0.50 kg, what average force does the punter exert on the ball?
The punter himself does not accelerate. The football does. So does his foot, but not as much as the ball does. If his own center of mass accelerated to 8 m/s in 0.21 seconds, we would be a world class sprinter.
The momentum change of the football,
8 m/s * 0.50 kg = 4.0 kg m/s
is equal to the impulse, F*0.21 s.
Solve for F.