Question

If the tennis ball were in contact with the ground for 0.0147 s, find the acceleration given to the tennis ball by the ground.

Answer 1

The acceleration is how fast speed of an object changes:

$$a=\frac{v_f-v_i}{t}=\frac{v_f-v_i}{0.0147}.$$

Notice: we need to know the initial and final velocities of the ball to find the value of acceleration. Be careful: if the ball rebounded, its initial velocity should be taken with a negative sign so that finally, in the numerator we add the magnitudes of velocities.