Hi all, i have been really stuck with this question for hours now, Two particles "P" and "Q" of masses 1Kg and 2Kg respectively are hanging vertically from the ends of a light inextensible string which passes over a smooth fixed pulley. The system is released from rest with both particles a distance of 1.5m above a floor. When the masses have been moving for 0.5s the string breaks. Find the futher time that elapses before "P" hits the floor. This has just got me totally confused, and to be honest i have no idea how to start, i have the picture drawn but am looking at it blankly. Any help is much appreciated. Daz.