Dynamics of Rotatory Motion

Angular Momentum
The angular momentum of this material point is the vector product of position vector and momentum ,

Angular Momentum (cont.)

Torque
We shall name the vector product of position vector and force as a moment of force about , or torque, ,

Newton’s Second Law
The angular momentum of a system of particles will change only if a torque exists

Moment of Inertia
The angular momentum of an object is equal to the product of the moment of inertia of this object and its angular velocity

Newton’s Second Law (cont.)
The angular acceleration of an object is directly proportional to the resulting moment of all external forces acting on this object and inversely proportional to the moment of inertia of the object