Bone has a Young's modulus of about
1.8 x 10^10 Pa. Under compression, it can
withstand a stress of about 1.59 x 10^8 Pa be-
fore breaking.
Assume that a femur (thigh bone) is 0.53 m
long, and calculate the amount of compression
this bone can withstand before breaking.
Answer in units of mm.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.