MHT CET 2017 Physics Solved Paper

A disc of moment of inertia ‘I1' is rotating in horizontal plane about an axis passing through a centre and perpendicular to its plane with constant angular speed ‘ω1’. Another disc of moment of inertia ‘I2’ having zero angular speed is placed co-axiallyon a rotating disc. Now, both the discs are rotating with constant angular speed 'ω2’. The energy lost by the initial rotating disc is