Question

The motion of a ball scooped by a field hockey player can be modeled by h=-16t^2+40t, where t is the time in seconds and h is the height of the ball. When will the ball reach 25 feet?
Solve with quadratic formula or completing the square or factoring, thank you!!

Answer 1

25 = -16t^2 + 40t

16t^2 - 40t  + 25 = 0

(4t - 5)(4t - 5) = 0

4t - 5 = 0

t = 5/4 = 1.25 seconds.