# Question #c5788

##### 1 Answer

The distances are **35 m** between the first two balls, **25 m** between the second and the third, and **15 m** between the third and the fourth.

#### Explanation:

Here's how you should approach this problem.

You know that the first ball you drop *reaches the ground* after **4 s** of free fall. The fact that they are released at *1 second* intervals after the first ball implies that the other three balls are still in the air whn the first one touches the ground.

The first thing you need to determine is the height from which the balls were dropped. The equation that you'll use looks like this

Use the time it took the first ball to reach the ground to determine the value of

Since the second ball is dropped *1 second* **after** the first one, it's only *3 seconds* into its free fall.

The height it reached after *3 seconds* will be

This means that the distance between the first two balls will be

In other words, the first ball dropped 35 meters **more** than the second ball.

The third ball was released *1 second* after the second, which is equivalent to *2 seconds* after the first ball.

The distance travelled by the third ball will be

This means that the distance between the second and third ball is

The fourth ball was released *1 second* after the third ball, so

The distance it covered is

Thus, the distance between the third and the fourth ball is