# Stress in a beam

thephysicsman

## Homework Statement

[PLAIN]http://img17.imageshack.us/img17/5112/ph2b.jpg [Broken]

a) This steel beam has a quadratic cross-section (A=100mm2). The force F is 10 kN. Calculate the stress in the rod and show that this stress does not exceed the yield strength of the steel.

[PLAIN]http://img600.imageshack.us/img600/1163/phya.jpg [Broken]

2. The attempt at a solution

a)

$$\sigma = \frac{10000N}{0.0001m^2}=100 MPa$$

I guess this is right? I'm not sure what the yield strength is. Can I calculate it from the given formulas?

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## Answers and Replies

Homework Helper
The result is okay, but note that [MPa] = [N/mm^2], and not [N/m^2], i.e. you didn't need to convert A into [m^2]. I'm not sure what the expressions in the image mean - are you given a yield strength for steel?

thephysicsman