Question

A basketball player, standing near the basket to grab a rebound, jumps 68.6 cm vertically. How much time does the player spend in the top 14.4 cm of his jump? How much time does the player spend in the bottom 14.4 cm of the jump?

Answer 1

total ascending and descending time t :
h = 0.686 = 0.5*g*t^2
t = √1.408/9.8 = 0.374 sec (374 msec)

ascending :
Vo = √2gh = 3.67 m/sec
(0.696-0.135) = 0.5*Vo*t1
t1 = (0.704-0.144)/(3.67*0.5) =0.305 sec
Δt1 = t-t1 = 0.374-0.305 = 69 msec

descending :
h2 = (0.686-0.144) = 0.5*g*t2^2
t2 = √0.542*2/9.8 = 0.333 sec
Δt2 = t-t2 = 0.374-0.333 = 41.0 msec