Question

A circular disc of mass m and radius r is set into motion on a horizontal floor .Find the magnitude of the total angular momentum

Answer 1

L = mvr + IW
I =mr^2/2
w=v/r
IW=mrv/2
L=3mvr/2

Answer 2

Image

Answer:  

Given that the disc of Mass 'M' with radius 'R' is rolling with angular speed 'w' on a horizontal plane.

Angular moment of rigid body in translations = Angular momentum of COM about O point + Angular momentum of body about COM

$L\quad =\quad m{ R }^{ 2 }w+IW$

$=\quad m{ R }^{ 2 }w+\left( \cfrac { m{ R }^{ 2 } }{ 2 } \right) { w}$

$=\quad \cfrac { 3 }{ 2m{ R }^{ 2 }w }$

The magnitude of the angular momentum of the disc about the origin 'O' is  

$\cfrac { 3 }{ 2m{ R }^{ 2 }w }$