The path of a falling object can be modeled by the functions h(t) = -16t2 + 64

Question

T is the time and h is the height..  How many seconds before the object hits the ground?  I know the answer is 2 seconds but how do I calculate it... Thank you..

Answer 1

h(t) = -16t^2 + 64

When the object hits the ground, the height above ground is clearly zero. Since the height above ground is zero, h(t) = 0.

We have:

h(t) = 0
-16t^2 + 64 = 0
16t^2 = 64
t^2 = 64 /16
t^2 = 4
t = sqrt(4)
t = 2

Hence, the answer is 2 seconds.