Question

A tennis ball is rolled off the edge of the roof of a building. Sean times how long it takes the ball to reach the ground and write the function h(t), that gives the height of the tennis ball in feet where t is the number of seconds since the ball cleared the edge of the roof. h(t)=-16t^2+256

After how many seconds does the tennis ball hit the ground? Show your work.

Answer 1

4

Explanation:

Solving for h(t) = 0, we find ...

0 = -16t^2 +256

0 = -t^2 +16 . . . . . . divide by 16

t^2 = 16 . . . . . . . . . .add t^2

t = 4 . . . . . . . . . . . . .positive square root

The ball hits the ground after 4 seconds.