Question

A ball is thrown from the top row of seats in a stadium. The function h(t) = - 16t^2 + 80t + 96 gives the height, in feet, of the ball t seconds after it is thrown. How long will it be before the ball hits the ground?

Answer 1

2s or 3s

Explanation:

Given the function that models the height of the object as;

h(t) = - 16t^2 + 80t + 96

The ball reaches the ground when h = 0

Substitute

0 = - 16t^2 + 80t + 96

Divide through by -16

0 = t²-5t-6

t²-5t-6 = 0

t²-2t-3t+6 = 0

t(t-2)-3(t-2) = 0

(tt-2)(t-3) = 0

t - 2 = 0 and t-3 = 0

t = 2 and 3s

Hence it will take the ball 2s or 3s to reach the ground