Question:

The femur bone in the human leg has a minimum effective cross section of about $3.0 \textrm{ cm}^2 \; (= 3.0 \times 10^{-4} \textrm{ m}^2)$. How much compressive force can it withstand before breaking?

Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.

Quick Answer:

$5.1 \times 10^4 \textrm{ N}$

### Transcript for this Giancoli solution

This is Giancoli Answers with Mr. Dychko. The maximum compressive stress that bone can withstand is 170 times 10 to the 6 newtons per square meter which we get from table [9-2] on page 245 and that equals force over area because stress is force divided by cross-sectional area. So we multiply both sides by*A*and then we get

*F*is

*A*times that compressive strength. And so area is 3.0 times 10 to the minus 4 square meters times 170 times 10 to the 6 newtons per square meter and you get 5.1 times 10 to the 4 newtons.