Question

A diver dives from a cliff with a height of 144 feet. His height, h, in feet is given by the equation h=-16t^2+144 , where t is the time in seconds the diver has fallen. How many seconds will it take for the diver to reach the water?

Answer 1

It takes 3 seconds for the diver to reach the water.

Explanation:

The height, in feet, is given by the following equation:

`h(t) = -16t^(2) + 144`

How many seconds will it take for the diver to reach the water?

He reaches the water when his height is 0, that is, when h(t) = 0. So

`h(t) = -16t^(2) + 144`

`0 = -16t^(2) + 144`

`16t^(2) = 144`

`t^(2) = (144)/(16)`

`t^(2) = 9`

`t = \pm √(9)`

`t = \pm 3`

There are no negative instant of time, so just t = 3.

It takes 3 seconds for the diver to reach the water.