Question

Molly is going to throw a ball from the top floor of her middle school. When she throws the ball from 128128 feet above the ground, the function h(t)=−16t2+32t+128h(t)=−16t2+32t+128 models the height, hh, of the ball above the ground as a function of time tt.Find when the ball hits the ground.

Answer 1

t = 4 seconds

Explanation:

Given that,

Molly is going to throw a ball from the top floor of her middle school. When she throws the ball from 128 feet above the ground, the function of its height is given by :

`h(t)=-16t^2+32t+128`

t is time in seconds

We need to find the time when it hots the ground. At this position, h(t) = 0. So,

`-16t^2+32t+128=0\\\\-t^2+2t+8=0`

On solving the above equation, we get

t = 4 second, t = -2 seconds

Ignoring t = -2 seconds

So, it will hit the ground at t = 4 seconds.