A disc of moment of inertia `I_(1)` is rotating freely with angular speed `omega_(1)` when another non-rotating disc of moment of inertia `I_(2)` is dropped on it. The two discs then rotate as one unit. Find the final angular speed.

A disc of moment of inertia `I_(1)` is rotating freely with angular sp

1.	A disc of moment of inertia `I_(1)` is rotating freely with angular speed `omega_(1)` when another non-rotating disc of moment of inertia `I_(2)` is dropped on it. The two discs then rotate as one unit. Find the final angular speed.
Answer» Here, initial angular momentum `L_(1) = I_(1) omega_(1)` Let `omega` be the final angular velocity of the combination. Therefore, final angular momentum. `L_(2) = (I_(1) + I_(2)) omega`. As `L_(2) = L_(1)` `:. (I_(1) + I_(2)) omega = I_(1) omega_(1)` `omega= (I_(1) omega_(1))/(I_(1) + I_(2))`

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A disc of moment of inertia `I_(1)` is rotating freely with angular speed `omega_(1)` when another non-rotating disc of moment of inertia `I_(2)` is dropped on it. The two discs then rotate as one unit. Find the final angular speed.

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