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- Homework Statement
- A uniform disk of mass M and radius R is rotating at an angular velocity of ##\omega## about it's center C. What is the angular momentum of the disk about an axis passing through A and perpendicular to the plane of disk.

- Relevant Equations
- ##I_c=\frac {MR^2} {2}##

##\vec L = I \vec {\omega}##

I am using the following formula to solve this problem.

$$ L_a= L_c + \text { (angular momentum of a particle at C of mass M)}$$

Because the point C is at rest relative to point A, so the second term in RHS of above equation is zero. Hence, the angular momentum about A is same as angular momentum about it's center of mass C.

$$\therefore L_a = \frac{MR^2}{2} ~ \omega$$.

I am not sure if above conclusion is correct.

$$ L_a= L_c + \text { (angular momentum of a particle at C of mass M)}$$

Because the point C is at rest relative to point A, so the second term in RHS of above equation is zero. Hence, the angular momentum about A is same as angular momentum about it's center of mass C.

$$\therefore L_a = \frac{MR^2}{2} ~ \omega$$.

I am not sure if above conclusion is correct.