Question

PLEASE HELP !!!

A ball is dropped from the top of a building with a height of 500 feet. The height of the ball at time t can be modeled by the function h(t)=−4.9t2+h⌄0 , where h⌄0 is the initial height of the ball. Approximately how long does it take for the ball to reach the ground?


Select one:

A. 10 seconds

B. 15 seconds

C. 4 seconds

D. 9 seconds

Answer 1

The answer to this question is A

Answer 2

A. 10 seconds

Explanation:

h(t) = -4.9t² + h

Plug in 500 for initial height:

h(t) = -4.9t² + 500

Height needs to be zero when the ball hits the ground:

0 = -4.9t² + 500

Solve for t:

-4.9t² + 500 = 0

-4.9t² = -500

t² = 102.041

t = 10.102, -10.102

Because time can't be negative, the ball will hit the ground after about 10 seconds