# Launching Tennis Balls into the Air with an Air Compressor

## How long does it take for a tennis ball launched directly upward with an initial velocity of 19 m/s to reach the ground again?

We have a vertical shoot, so we will calculate the time of flight. In order to find the time, we can use the formula:

**t = 2vi/g**

where vi is the initial velocity, g is the gravity, and t is the time.

## Answer:

The ball takes approximately 3.9 seconds to reach the ground again.

Shiloh is using an air compressor to launch tennis balls into the air. One ball that she launches directly upward has an initial velocity of 19 m/s. To calculate the time it takes for the ball to reach the ground again, we use the formula for time of flight:

**t = 2vi/g**

Given that vi = 19 m/s and g = 9.8 m/s^2, we substitute these values into the formula:

**t = 2(19)/9.8 = 3.87 seconds ≈ 3.9 seconds**

Therefore, it will take approximately 3.9 seconds for the tennis ball launched with an initial velocity of 19 m/s to reach the ground again.