A horizontal disc rotates freely about a vertical axis through its centre. A ring having the same mass and radius as the disc is now gently placed on the disc After same time, the two rotate with a common angular velocity

A horizontal disc rotates freely about a vertical axis through its cen

1.	A horizontal disc rotates freely about a vertical axis through its centre. A ring having the same mass and radius as the disc is now gently placed on the disc After same time, the two rotate with a common angular velocity
Answer» some friction exists between the DISC and the rind the angular momentum of the disc plus ring is CONSERVED the FINAL common angular angular velocity is `2//3^("RD")` of the initial angular velocity of the disc `2//3^("rd")` of the initial kinetic energy CHANGES to heat Answer :A::B::D