Question

A punter kicks a football upward with an initial speed of 48 feet per second. After how many seconds does the ball hit the ground? Use the formula h = rt − 16t2 where h represents height in feet and r represents the initial speed

Answer 1

check the picture below. That's pretty much a rough graph of an initial speed scenario.

so, we know the ball will hit the ground when h = 0, and we know that r = 48, thus

`image`

Answer 2

3 seconds.

Explanation:

We have been given that a punter kicks a football upward with an initial speed of 48 feet per second. Use the formula
`h=rt-16t^2` to find after how many minutes ball will hit the ground.

The ball will hit the ground, when height, h equals to 0.

`h=48t-16t^2`

`0=48t-16t^2`

`-16t^2+48t=0`

`-16t(t-3)=0`

Using zero product property, we will get:

`-16t=0\text{ or }(t-3)=0`

`t=0\text{ or }t-3=0`

`t=0\text{ or }t=3`

Therefore, after 3 seconds ball will hit the ground.