A rocket with mass $\mathrm{m}$ and flow rate $\mathrm{m}$ at velocity u travels on a horizontal circular wire of radius $\mathrm{r}$ and friction coef-
ficient $\mu$. The constant velocity with which it travels is (neglect gravity)
(a) $\frac{\mathrm{m}}{\mathrm{m}} \frac{\mathrm{u}}{\mu}$