Question

A ball is thrown from the top of the school. The height of the ball (in feet) written in

terms of the time (in seconds) is modeled by f (t) = -16t² + 32t + 48. At what time
will the ball hit the ground?

Answer 1

3 seconds

Explanation:

When the ball hits the ground, the height will be 0. Therefore, you can substitute 0 in for the value of f(t), hence the equation will be:

0 = -16t^2 + 32t + 48

You can then factor out -16:

0 = t^2 - 2t - 3

Factor:

0 = (t-3)(t+1)
t = 3, -1

However -1 is an extraneous solution because time cannot be negative. Therefore, the answer is 3 seconds.