An object at a height of 24 feet is thrown upward with an initial velocity of 8 feet per second. When will the object hit the ground?

We put the acceleration of gravity, the initial velocity and the initial height all together to get our formula for height as a function of time:

y = - 16t² + 8t + 24

We want to know when y=0

0 = - 16t² + 8t + 24

0 = 2t² - t - 3

0 = (t + 1) (2t - 3)

t = - 1 or t=3/2

We reject the negative root.

Answer: 1.5 seconds later