Motion of a rigid body in two dimensions: Equations of motion in two dimensions, Kinetic energy of a rigid body, Moment of Momentum, Rolling and sliding Friction, Rolling of a sphere on a rough inclined plane , Sliding of a Rod, Sliding and Rolling of a Sphere on an inclined plane, Sliding and Rolling of a sphere on a fixed sphere. Equations of motion of a rigid body under impulsive forces, Impact of a rotating Elastic sphere on a fixed horizontal Rough plane. Change in K.E. due to the action of impulse.