speed is 0 at the top so to get time to top
0 = Vi - 9.81 t
Vi = 9.81 t
then do height at that top t
4.8 = 1.2 + Vi t - 4.9 t^2
3.6 = 9.81 t^2 - 4.9 t^2
4.9 t^2 = 3.6
t = .857 second
Vi = (9.81 ) .857 = 8.41 m/s
A gymnast bounces upward from a trampoline at an initial height of 1.2m and reaches a maximum height of 4.8m before falling back down. What was his initial speed?
1 answer