1. The problem statement, all variables and given/known data A ball is thrown vertically upwards and its height after t s is s m where s= 25.2t - 4.9t2 Find the distance moved in the 3rd second 2. At the instant from which time is measured a particle is passing through O and travelling towards A along the straight line OA. It is s m from O after t s where s= t(t-2)2 What is the particle's greatest displacement from O, and how far does it move, during the first 2 s? 3. The attempt at a solution 1. 25.2(3)-4.9(9) = 31.5m Is the answer not 31.5m? But my book has a different answer. 2. For the greatest displacement I believe it is (32/27)m but for the displacement after the first 2 seconds I'm not sure, cause if I put it in the formula for s I'll get 0. Help is greatly appreciated.