Question

While working on a roof, Rob dropped his hammer. The hamer's fall can be represented by the equation h=-16t^2+20 (where t=time in seconds and h=height in feet) How long will it take the hammer to reach the ground?

Answer 1

Answer:

It will take 1.12 seconds for the hammer to reach the ground.

Step-by-step explanation:

The height of the hammer after t seconds is given by the following equation:

$h(t) = -16t^{2} + 20$

How long will it take the hammer to reach the ground?

This is t for which h(t) = 0. So

$h(t) = -16t^{2} + 20$

$-16t^{2} + 20 = 0$

$16t^{2} = 20$

$t^{2} = \frac{20}{16}$

$t^{2} = \frac{1.25}$

$t = \pm \sqrt{1.25}$

Time is a positive measure, so

$t = 1.12$

It will take 1.12 seconds for the hammer to reach the ground.