Max Height to Jump Without Breaking Leg Bones

[ussjt]

Could someone help me set up this problem and give some helpful hints.

From what maxium height can a 75-kg person jump without breaking the lower leg bone on either leg? Ignore air resistance and assume the CM of the person moves a distance of .60m from standing to the seated position (that is, in breaking the fall). Assume the breaking strenght (force per unit area) of bone is 170 * 10^6 N/m square, and its smallest crosssectional area is 2.5 * 10^-4 m square.

 

[enigma]

Have you tried it yet?

Conservation of energy.

$$\int{Fds} = mgh$$

 

[ussjt]

no, because I need help with the set up for each section...I have been out for a couple days so I don't fully understand the problem. If I knew the equations for each step, I could take it from there.

 

[enigma]

I more or less gave it to you already.

You know the breaking stress, and the bone's area. Stress is force divided by area. ->solve for force.

You know the force and the distance that force can act on. You know the mass, you know gravity, solve for height.