Angular Momentum?

Question

A cylinder of mass 'm' and radius 'r' is rolling witout slipping on a horizontal surface.Find total angular momentum about a point 'p' at a distance 'r/2'above the center.

Answer 1

Ok, I can give you an idea :

You can use the Steiner's law :

Ia = Ic + m*a^2

a = distance from the center = r/2

Ia = Mr^2 / 2 + M*(r/2)^2

Ia = 3Mr^2 / 4

So the angular momentum will be : 3Mr^2 / 4*w

Answer 2

you can't find angular momentum anywhere ,you can only find where total torque is 0 and then you can apply mvr=Iw.