(b) Show that the centre of mass of a system of particles moves as if the total external force were acting in the entire mass of the system concentrated at the center of mass(7 marks)
(c) The position vectors of masses 2 kg, 3kg and 4kg are 2i-3j, i+j+k and 4j+3k
respectively. If their respective velocities are -31, 6j and 2i+3k units, calculate
(i) the radius of the center of mass(3 marks)
(ii) the velocity of the center of mass(3 mark)
(iii) the angular momentum vector about the origin (5 marks)