Angular Momentum



ANGULAR MOMENTUM
.
The measure of the quantity of motion possessed by a body in rotational motion is called ANGULAR MOMENTUM.
Definition

Angular momentum of a body is defined as :
“The angular momentum of a body about an axis is the product of its linear
momentum and the perpendicular distance of the body from the axis.”
In other words
“The angular momentum of a body is equal to cross product of its
linear momentum and the vector distance from the axis of rot
ation.”
Mathematical representation
If a body of mass “m” is moving in a circle or radius with velocity , the linear momentum of body is
The angular momentum of the body is given by:
= X
Putting the value of
= X m

Magnitude of Angular momentum


Since

Angle between and is equal to 90o
L = m rv sinq
L = m rv sin90
L = m rv (1)
L = m r v
But v = rw
L = m r(rw)
L = m r2w
We know that m r2 is equal to moment of inertia i.e. I = m r2
Thus
Unit of Angular momentum

In S.I. System unit of angular momentum is “joule.second“.
Dimension of Angular momentum
[L2MT -1]