Question

An object is dropped from a bridge and allowed to freefall to the ground. The height of the object over time can be modeled using h(t) = 144 – 16t2.

How many seconds will it take the object to reach the ground?

Answer 1

When the object reaches the ground, the height is zero, so:
0 = 144 - 16t^2
then you just solve for t, so subtract the 144 over
-144 = -16t^2
then divide by the -16
9 = t^2
then take the square root of both sides
3 = t
therefore, it will take three seconds for the object to reach the ground.