Question

If an object is dropped from a height of 55 feet, d=-16t2+65 gives the height of the object after t seconds

Answer 1

Plug in d = 0 and solve for t
d = -16t^2 + 55
0 = -16t^2 + 55
-55 = -16t^2
t^2 = -55/(-16)
t^2 = 55/16
t = sqrt(55/16)
t = 1.854

It takes approximately 1.854 seconds for the object to hit the ground