You are playing volleyball. You hit the volleyball with an initial vertical velocity of 15 feet per second when it is 4 feet above the ground. Find how many seconds it takes to reach the maximum height, the maximum height reached, and the time the object is in the air.

Answer 1

a. V = Vo + g*t
Tr = (V-Vo)/g = (0-15)/-32 = 0.469 s. To
reach max. Ht. = Rise time.

b. h = ho + Vo*t + 0.5g*t^2
h = 4 + 15*0.469 - 16*(0.469)^2=7.52Ft.
Above Gnd.

c. h = Vo*t + 0.5g*t^2 = 7.52 Ft.
0 + 16*T^2 = 7.52
T^2 = 0.469
Tf = 0.685 s. = Fall time.

T = Tr + Tf = 0.469 + 0.685 = 1.15 s. in
air.