Physics · 2021
JEE Main · 27 August 2021, Shift 2 · Q3
Two discs have moments of intertia I_1 and I_2 about their respective axes perpendicular to the plane and passing through the centre. They are…
Two discs have moments of intertia $\displaystyle \mathrm{I}_1$ and $\displaystyle \mathrm{I}_2$ about their respective axes perpendicular to the plane and passing through the centre. They are rotating with angular speeds, $\displaystyle \omega_1$ and $\displaystyle \omega_2$ respectively and are brought into contact face to face with their axes of rotation coaxial. The loss in kinetic energy of the system in the process is given by :
Official answer
(1)
$\displaystyle \frac{\mathrm{I}_1 \mathrm{I}_2}{2\left(\mathrm{I}_1+\mathrm{I}_2\right)}\left(\omega_1-\omega_2\right)^2$
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JEE Main 2021 Physics question, with the answer from NTA’s final answer key. Where our answers come from.