A 0.5-kg rubber ball is dropped from rest a height of 19.6 m above the surface of the Earth. It strikes the sidewalk below
and rebounds up to a maximum height of 4.9 m. What is the magnitude of the impulse due to the collision with the sidewalk?
The Attempt at a Solution
Just before collision:
Just after collision:
J=m(vafter-vbefore)=.5(9.8-19.6)=4.9 kg m/s
The answer is 14.7 N.s, so I'm not sure what I'm missing.