Answer:
t = 7.5 seconds
Step-by-step explanation:
Givens
vi = 120 f/s
a = -32 f/s
d = 0 It goes up, stops and comes back down landing where it starts.
Formula
d = vi*t + 1/2 a t^2
Solution
0 = 120*t - 1/2*32*t^2 transfer 120t to the left
-120*t = - 1/2 32 t^2 Multiply 32 and 1/2 together
- 120t = - 16 t^2 Divide both sides by t
-120 = -16 t Divide by -16
-120/-16 = (-16/-16) * t
t = 7.5 seconds
