A tennis ball with mass 100 g is moving horizontally at 20 m/s. it hits a brick wall and bounces back with exactly the same speed but moving in the opposite direction. if the average force on the ball is 200 n, how long are the ball and wall in contact?
(a) 2 ms
(b) 200 ms
(c) 2 s
(d) 2 μs
(e) 20 ms
