A 58.0 g incoming tennis ball has a speed of 30 m/s when it is hit by a racket in the opposite direction and leaves the racket at 40 m/s. What
is the average force exerted by the racket on the ball if contact lasted
for 5.2 ms?

The racket applies an average acceleration of

(Note that I'm taking the initial direction of the ball's motion to be negative.)

Then the average force exerted on the ball is

the focus of lesson 1 is newton's first law of motion - sometimes referred to as the law of inertia. newton's first law of motion is often stated as. an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

explanation:

so easy. just google the electromagnetic waves and it’ll pop up.