[SOLVED] simple collisions question 1. The problem statement, all variables and given/known data http://img180.imageshack.us/img180/1253/28157442gm4.jpg [Broken] 2. Relevant equations √(2gh) 3. The attempt at a solution a) Gravitational potential energy = kinetic energy this gives u √(2gh) = 0.815 metres b) i) In a closed system, total momentum is always conserved. ii) Momentum before = momentum after momentum before : mass X velocity (80/100) kg X 4 m/s = 0.32kgm/s momentum after : mass X velocity ((80/100) X 3) kg X x = 0.32 kgm/s therefore x = 1.33 m/s Is that rite? and for c) : ah i get it now!!!