how tall is the building? when did it hit the ground? what was the height at 2 seconds?

Question

a brick is dropped off of a building. its path can be modeled by h(t)=-16^{2}+144, where h(t) is the height in feet after 't' seconds.

Answer 1

McKenzie, you left off the t in the formula.

h(t) = -16t² + 144

The height is h(t) at t = 0, 144

The height at 2 seconds is h(2), -16 * 2² + 144 = -16 * 4 + 144 = 80

It hits the ground when h(t) = 0

-16t² + 144 = 0

16t² = 144

t² = 144/16 = 9

t = 3 (we throw out the negative solution).