Question

A 57.8 kg pole-vaulter falls from rest from a height of 5.4 m onto a foam-rubber pad. The pole-vaulter 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 pole-vaulter due to the collision.
_________N upward

Answer 1

(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