Q 11-04-063JEE MainJEE Main 2026 (24 Jan, Shift 2)Medium
A flexible chain of mass $m$ hangs between two fixed points at the same level. The inclination of the chain with the horizontal at the two points of support is $30^\circ$. Considering the equilibrium of each half of the chain, the tension of the chain at the lowest point is ______ .
Answer: (B) $\dfrac{\sqrt3}{2}mg$
Let $T$ be the tension at each support. For the whole chain, the vertical components balance the weight:
$$2T\sin30^\circ = mg\Rightarrow T = mg$$
For one half of the chain, the tension $T_0$ at the lowest point is horizontal and balances the horizontal component at the support:
$$T_0 = T\cos30^\circ = \frac{\sqrt3}{2}mg$$
Solution by Sreeraj P, M.Sc Physics