Browse Questions

# A disc of mass M and radius R is rolling with angular speed w on a horizontal plane as shown. The magnitude of the angular momentum of the disc about the origin O is :

$\begin {array} {1 1} (a)\;(1/2) MR^2 w & \quad (b)\;MR^2w \\ (c)\;\frac{3}{2} MR^2 w & \quad (d)\;2MR^2w \end {array}$

Angular moment of rigid body in translations cum rotation = Angular momentum of COM about O point + Angular momentum of the body about COM
$L= mR^2 w +I W$
$\quad= mR^2w + \large\frac{mR^2}{2} w$
$\quad= \large\frac{3}{2}$$mR^2 w$
edited Jun 22, 2014