Problem 59P

(II) A nonrotating cylindrical disk of moment of inertia I is dropped onto an identical disk rotating at angular speed co. Assuming no external torques, what is the final common angular speed of the two disks?

Step-by-step solution

Step 1 of 2

The cylindrical disk of the moment of inertia I is rotating with an angular speed

Then a non rotating cylindrical disk of the same moment of inertia I is dropped on the rotating cylinder.

As the net torque = 0, hence the angular momentum is conserved.

The coupled system now has rotational inertia

And let the final angular speed of this coupled system be