JEE Mains · Physics · STD 11 - Motion in plane
- JEE Mains 2025
- Hard
- Numerical

A string of length \(L\) is fixed at one end and carries a mass of \(M\) at the other end. The mass makes \(\left(\frac{3}{\pi}\right)\) rotations per second about the vertical axis passing through end of the string as shown. The tension in the string is \(\ldots\ldots\) ML.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) 36
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \omega=\frac{3}{\pi} \times 2 \pi=6 \mathrm{rad} / \mathrm{s} \\ & R=L \sin \theta\end{aligned}\)

and \(T=M \sqrt{g^2+\omega^4 R^2}\)
Also, \(T \sin \theta=M \omega^2 \cdot L \sin \theta\)
\(\begin{aligned}
& \Rightarrow \quad T=M(36) \mathrm{L} \\
& \Rightarrow \quad T=36 \mathrm{ML}
\end{aligned}\)

and \(T=M \sqrt{g^2+\omega^4 R^2}\)
Also, \(T \sin \theta=M \omega^2 \cdot L \sin \theta\)
\(\begin{aligned}
& \Rightarrow \quad T=M(36) \mathrm{L} \\
& \Rightarrow \quad T=36 \mathrm{ML}
\end{aligned}\)
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