Question 687: Centre of Mass and Rotational Motion

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 $$I$$1 rotating with an angular velocity $$\omega $$ about the same axis. The final angular velocity of the combination of discs is

Accepted Answer

The initial angular momentum of the system is
$${I_1}\omega $$ and final angular momentum is $$\left( {{I_1} + {I_2}} \right)\omega '$$
where
$$\omega '$$ = final angular velocity of combination of discs
On equating the initial and final angular
momentum, we get
$$\omega ' = {{{I_1}\omega } \over {\left( {{I_1} + {I_2}} \right)}}$$

Answer

$${{{I_2}\omega } \over {{I_1} + {I_2}}}$$

Answer

$$\omega $$

Answer

$${{{I_1}\omega } \over {{I_1} + I{}_2}}$$

Answer

$${{\left( {{I_1} + {I_2}} \right)\omega } \over {{I_1}}}$$

Centre of Mass and Rotational Motion

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 I1 rotating with an angular velocity \omega $ about the same axis. The final angular velocity of the combination of discs is

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