Posted by **Wolves** on Thursday, June 27, 2013 at 10:38am.

A cylinder with moment of inertia 22.1 kg m2 rotates with angular velocity 5.71 rad/s on a frictionless vertical axle. A second cylinder, with moment of inertia 28.3 kgm2, initially not rotating, drops onto the first cylinder and remains in contact. Since the surfaces are rough, the two eventually reach the same an- gular velocity.