Two particles P P\,P and Q Q\,Q move along the same straight line. At t=0t=0t=0, P P\,P passes a point O O\,O with speed 4 m s-1 and constant acceleration 2 m s-2. At the same instant, Q Q\,Q is 18 m ahead of O O\,O and moves in the same direction with constant speed 10 m s-1.
Find the time at which P P\,P catches QQQ.