physics
posted by jamie .
A high jumper wants to clear the bar at 2.1m. To do so he needs to raise his center of mass to a height of 2.4m. Assuming that air resistance can be neglected and his center of mass is 1.1m above the ground at takeoff, determine the required vertical takeoff speed.

The jumper has to raise his center of
mass to the height of 2.4, i.e. to move
it by the distance of 2.4 1.1 =1.3 m
From kinematics
h =Vo•tg•t^2/2,
0=Vo –gt
Vo=sqrt(2•g•h) =sqrt (2•9.8•1.3) =5.05 m/s