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

Answer:

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

Step-by-step 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

$h(t) = -16t^{2} + 144$

$0 = -16t^{2} + 144$

$16t^{2} = 144$

$t^{2} = \frac{144}{16}$

$t^{2} = 9$

$t = \pm \sqrt{9}$

$t = \pm 3$

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

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