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Byju's Answer

Standard XII

Physics

Perpendicular Axis Theorem

A round disc ...

Question

A round disc of moment of inertia $I_{2}$ about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia $I_{2}$ rotating with an angular velocity $ω$ about the same axis. The final angular velocity of the combination of disc is :-

ω

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\frac{I_{1} ω}{I_{1} + I_{2}}

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\frac{(I_{1} + I_{2}) ω}{I_{1}}

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\frac{I_{2} ω}{I_{1} + I_{2}}

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Solution

The correct option is A $ω$
Conservation of angular momentum
$I_{1} ω = (I_{1} + I_{2}) ω_{f}$
$ω_{f} = \frac{I_{1} ω}{I_{1} + I_{2}}$

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A round disc of moment of inertia I2 about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia I2 rotating with an angular velocity ω about the same axis. The final angular velocity of the combination of disc is :-

The correct option is A ωConservation of angular momentumI1ω=(I1+I2)ωfωf=I1ωI1+I2

A round disc of moment of inertia $I_{2}$ about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia $I_{2}$ rotating with an angular velocity $ω$ about the same axis. The final angular velocity of the combination of disc is :-

The correct option is A $ω$
Conservation of angular momentum
$I_{1} ω = (I_{1} + I_{2}) ω_{f}$
$ω_{f} = \frac{I_{1} ω}{I_{1} + I_{2}}$