Question

A tennis ball of mass 57 g travels with velocity < 74, 0, 0 > m/s toward a wall. After bouncing off the wall, the tennis ball is observed to be traveling with velocity < -70, 0, 0 > m/s.
What is the change in the magnitude of the tennis ball's momentum?

Answer 1

Answer:

0.228 kgm/s

Explanation:

57 g = 0.057 kg

The momentum of the tennis ball before hitting the wall is the product of its velocity and mass

$p_1 = mv_1 = 0.057 * 74 = 4.218 kgm/s$

The momentum of the tennis ball after hitting the wall is

$p_2 = mv_2 = 0.057 * (-70) = -3.99 kgm/s$

We we want to calculate the change in magnitude of the momentum, we take the difference between their absolute values:

$\Delta p = |p_1| - |p_2| = 4.218 - 3.99 =0.228 kgm/s$