If a metal ball is thrown downward with an initial velocity of 22 feet per second (15mph)from a 100 foot water tower, it's height h in feet above the ground after t seconds is modeled by h(t)=-16t^2-22t+100

Question

Determine when the height of the ball is 62 feet.

Answer 1

h = 100 - 22 t - 16 t^2
62 = 100 - 22 t - 16 t^2
16 t^2 + 22 t - 38 = 0

8 t^2 + 11 t - 19 = 0
(8 t + 19) (t - 1) = 0
t = 1 second (forget the negative time)