A particle of mass 1.5 kg is resting on a smooth horizontal table. The particle is attached to a light, inextensible string of length 2.5 m. This string is passed through a smooth hole in the table. At the other end of the string is a particle of mass 4 kg. The particle on the table is set in motion and describes circles with radius 1.5 m. Find the speed of the particle on the table. Assume that the particle that is freely hanging does not move during the motion.