## Physics (10th Edition)

The tension in the cord provides the centripetal force, so $$T=F_c=\frac{mv^2}{r}$$ $m$ and $v$ are the same for both stones, but $r_1=2r_2$. Therefore, $$\frac{T_1}{T_2}=\frac{\frac{mv^2}{r_1}}{\frac{mv^2}{r_2}}=\frac{r_2}{r_1}=\frac{1}{2}$$ (d) is correct.