Parviz F. answered • 12/31/13

Tutor

4.8
(4)
Mathematics professor at Community Colleges

h = -16t^2 + 320t + 32

Ground is h =0.

- 16 t^2 + 320 t + 32 = 0.

- t^2 + 20 t + 2 =0

t = -20/2 ±(√(400 + 8)

2

t = -10 + √408 = 10.2 sec / negative answer is not acceptable.