Separation of Motion of a system of particles into motion of the centre of mass and motion about the centre of mass :
Show `(dL')/(dt)=sum r'_1xx(dp')/(dt)` Further, show that `(dL')/(dt)=τ'_(ext)` where `τ'_(ext)` is the sum of all external torques acting on the system about the centre of mass. (Hint : Use the definition of centre of mass and Newton’s Third Law. Assume the internal forces between any two particles act along the line joining the particles.)