Question

A fireworks rocket is shot vertically up in the air. The quadratic function h(t) = −16t^2 + 176t models the height of the rocket above the ground after t seconds. How long does it take for the rocket to return to the ground? HELP ASAP

3 seconds
7 seconds
11 seconds
15 seconds

Answer 1

Hi there!

The answer would be 11 seconds.

Hope it helps you :)

Answer 2

Hi there! The answer is 11 seconds.

We want to find out when the height of the rocket equals 0 (because then it'll be on the ground). When we know this we can set up an equation.


`- 16 {t}^(2) + 176t = 0`

`- 16t(t - 11) = 0`


`- 16t = 0 \: \: \: \: or \: \: \: \: t - 11 = 0`

`t = 0 \: \: \: \ \: \: \: \: \: \: \: \: or \: \: \: \: t = 11`
Therefore the rocket will be returned in the ground after 11 seconds.