A ball of mass m is dropped onto a floor from a certain height. The collision is perfectly elastic and the ball rebounds to the same height and again falls. Find the average force exerted by the ball on the floor during a long time interval.

Explanation

To find the average force exerted by a ball of mass \( m \) on the floor during a long time interval when it is dropped from a height \( h \) and rebounds elastically, we can follow these steps:

### Step-by-Step Solution:

1. **Determine the Velocity Just Before Impact:**
When the ball is dropped from a height \( h \), we can use the third equation of motion to find the velocity just before it hits the ground. The equation is:
\[
v = \sqrt{2gh}
...