Question

PLEASE HELP
The height of a snowball thrown off a 128-foot cliff is modeled by the function h(t) = −16t2 + 64t + 192, where h is height in feet and t is time in seconds. Find the time the snowball takes to reach the ground.
6 seconds
3 seconds
4 seconds
5 seconds

Answer 1

When it reaches the ground h(t) = 0 so we have:-

-16t^2 + 64t + 192 = 0

-16(t^2 - 4t -  12) = 0

-16(t  - 6)(t + 2) = 0

t = 6, -2

Answer is 6 seconds