# 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 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:  =  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 Butv = 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]