Physics · 2021
JEE Main · 17 March 2021, Shift 1 · Q6
A mass M hangs on a massless rod of length l which rotates at a constant angular frequency. The mass M moves with steady speed in a circular path of…
A mass M hangs on a massless rod of length $\displaystyle l$ which rotates at a constant angular frequency. The mass M moves with steady speed in a circular path of constant radius. Assume that the system is in steady circular motion with constant angular velocity $\displaystyle \omega$. The angular momentum of M about point A is $\displaystyle \mathrm{L}_{\mathrm{A}}$ which lies in the positive $\displaystyle z$ direction and the angular momentum of M about point B is $\displaystyle \mathrm{L}_{\mathrm{B}}$. The correct statement for this system is :
Official answer
(2)
$\displaystyle \mathrm{L}_{\mathrm{A}}$ is constant, both in magnitude and direction
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JEE Main 2021 Physics question, with the answer from NTA’s final answer key. Where our answers come from.