A structural steel has a yield strength of 250 MPa and a Modulus of Elasticity of 200 GPa. Calculate its Modulus of Resilience.

A weight $W = 500 N$ is dropped from a height $h = 200 mm$ onto a rigid collar at the end of a vertically hanging steel rod. The rod has a length $L = 3 m$, area $A = 100 mm^2$, and $E = 200 GPa$. Determine the maximum dynamic stress developed in the rod.