Question

The height of a football after it's been kicked from the top of a hill is h=2(-2-4t)(2t-5) where h is height and t is time in seconds how long was football in the air?

Answer 1

2.5 seconds.

Explanation:

When the football reaches the ground h = 0, so:

2(-2 - 4t)(2t - 5) = 0

so either -2 - 4t = 0 or 2t - 5 = 0

so -4t = 2 or 2t = 5

t = -1/2 , t = 5/2 = 2.5 seconds.

WE ignore the negative t , so

Time that the ball was in the air = 2.5 seconds.