In the high jump, the kinetic energy of an athlete is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must the athlete leave the ground in order to lift his center of mass 1.55 m and cross the bar with a speed of 0.70 m/s(adsbygoogle = window.adsbygoogle || []).push({});

I have tried solving this problem by using the formulas for kinetic and potential energy. I thought that the initial kinetic energy would equal the potential energy plus the kinetic energy in the air.

KE = PE + KE'

.5(m)(v^2) = m(g)(h) + .5(m)(v^2)

Then i figured i could cancel out mass since it is in all parts

.5(v^2) = (9.81)(1.55) + .5(.7^2)

v= Sqrt (15.205 + .245)

v = 30.9

This is the wrong answer, and i am not sure what i am doing wrong. Please help.

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# Homework Help: High Jump

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