The centre of mass of a system of particles moves as if all the _________ of the system was concentrated at the _________ of mass and all the external forces acting on the system were applied directly at this point.

Define centre of mass of a system of particles.

Does the centre of mass of a system of two particles lie on the line joining the two particles?

Determine the co-ordinates of centre of mass of a system of n particles.

Fill in the blanks: When no external force acts on a system the total _____ of the system remains constant.

Can KE of a system be increased or decreased without the application of external force?

The net external torque on a system of particles about an axis is zero. Which of the following are compatible with it?

Separation of mmotion of a systme of particles into motion of the centre of mass and motion about the centre of mass Show K = K + 1/2 MV^2 , where k is the total kinetic energy of the system of particles, K is the total kinetic energy of the system when the particle velcoities are taken with respect to the centre of mass and MV^2//2 is the kinetic energy of the translation of the system as a whole (i,e of the centre of mass motion of the system).