Posted by Becky on .
A 57.8 kg polevaulter falls from rest from a height of 5.4 m onto a foamrubber pad. The polevaulter comes to rest 0.25 s after landing on the pad.
(a) Calculate the athlete's velocity just before reaching the pad.
______ m/s downward
(b) Calculate the constant force exerted on the polevaulter due to the collision.
_________N upward

Physics 
Damon,
(1/2) m v^2 = m g h
so
v = sqrt (2 g h)
Force = rate of change of momentum (m a in the limit as t>0 and with constant m)
F = change in momentum/change in time
= m v /t