A heavy uniform rod of mass $m$, length $L$, and cross-sectional area $A$ hangs vertically from a ceiling. Find the total elongation $\Delta L$ due to its own weight.
2.
A steel wire of radius $r$ and length $L$ is fixed at one end and rotated in a horizontal circle with angular velocity $\omega$ carrying a mass $M$ at its free end. Find total elongation of the wire.
