UPSEE 2019 Solved Paper

Here, disc has two types of motion namely translational and rotational. Hence, angular moment of a rigid body in translational cum rotational
= angular momentum of centre of mass about origin (O)+ angular momentum of the body about centre of mass.
⇒L=MR2ω+I.ω
Here, I=

MR2

2

(for disc ) and ω= angular velocity of the rigid body
=MR2ω+(

MR2

2

)ω
=

3

2

MR2ω