An iron rod 4.00m long and 0.500cm^2 in cross-section stretches 1.00mm when a mass of 225kg is hung from its lower end. compute young's modulus for the iron

Question

anonymous · Answer

The change in length (either by compression or tension) is:

$$\Delta L = \frac{FL_{0}}{YA}$$

where $Y$ is the Young Modulus, $A$ is the cross sectional area where the force is acting and $L_{0}$ is the original length.

You have all the variables (the force can be found from $mg$), except $Y$. You just need to write the equation in term of the Young Modulus and solve for it.