The potential energy of a two-atom system is $U(r) = \frac{a}{r^{12}} - \frac{b}{r^6}$. Find equilibrium distance $r_0$ and dissociation energy.
2.
A bullet of mass $m$ penetrates a block of mass $M$ suspended by a string of length $L$ and gets embedded in it. Find minimum bullet velocity $v_0$ so block completes a vertical circle.
