A tennis ball (m 0.2 kg) is thrown at a brick wall. It is
traveling horizontally at 12 m/s just before hitting the
wall and rebounds from the wall at 8 m/s, still traveling
horizontally. The ball is in contact with the wall for 0.04 s.
What is the magnitude of the average force of the wall on
The Attempt at a Solution
I didn't even know where to begin to I went to the solutions manual which did this:
[-(0.2kg)(8ms)-(0.2kg)(12ms)] / 0.04s = -100N; magnitude would be 100
Where the crap is the negative sign coming from?!