$7\mathrm{.}43.$ A rod is supported by two wheels spinning in opposite directions. Ifthe wheels were horizontal, the rod would he placed centrally over the wheels for equilibrium. However, the wheels have an inclination of $20$ as shown, and the rod must he placed at a position off center for equilibrium. If the coefficient of friction is ${}_{i,}=8,$ how many lect off center musis the rod he placed?

Figure P$\mathrm{.}7\mathrm{.}43$