Angular Momentum
ANGULAR MOMENTUM


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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 rotation.”

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: 

Putting the value of 



Magnitude of Angular momentum


Since 
Angle between and is equal to 90^{o}


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 r^{2}w

We know that m r^{2} is equal to moment of inertia i.e. I = m r^{2} 
Thus 

Unit of Angular momentum


In S.I. System unit of angular momentum is “joule.second“. 
Dimension of Angular momentum


[L^{2}MT ^{1}]
