A gymnast does a one-arm handstand. The humerus, which is the upper arm bone between the elbow and the shoulder joint, may be approximated as a 0.26-m-long cylinder with an outer radius of 1.12 x 10-2 m and a hollow inner core with a radius of 3.7 x 10-3 m. Excluding the arm, the mass of the gymnast is 58 kg. Bone has a compressional Young's modulus of 9.4 x 109 N/m2. (a) What is the compressional strain of the humerus? (b) By how much is the humerus compressed?(adsbygoogle = window.adsbygoogle || []).push({});

Ok here is what I have so far on this problem I know that I'm suppose to find the Cross sectional area (A) in this problem. But I'm not sure how I would go about doing that with the 2 radius. Do I find the area of each and add them together? Or perhaps subtracting them?

I know that I'm suppose to use the formula F = Y (Delta L/ L0) (A) . Y = Youngs Modulus, Delta L = Change in Length/ L0 is initial Length, A = crossectional area.

The force applied here would be (58 kg)(9.8 m/s) right? The F value

young's Modulus is given as well as the initial length.

I know that to find the strain it is the ratio between Delta L and L0 right? And to find the change in how much it is compressed by solving for the Delta L.

So my main difficulty is thecross sectional areaof this problem and perhaps not working right to find the total force?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Another Diffcult Bone Compression problem.

**Physics Forums | Science Articles, Homework Help, Discussion**