1. The problem statement, all variables and given/known data An object at rest explodes into three pieces of masses 5.00 kg, 10.0 kg and 20.0 kg. The 5.00 kg piece moves west at 30.0 m/s; the 10.0 kg piece moves southwest at 20.0 m/s. What is the velocity of the 20.0 kg piece and what direction is it moving? 2. Relevant equations Conservation of kinetic energy 3. The attempt at a solution My thinking is to use conservation of kinetic energy. I begin by writing out the equation with one mass before and three after. The energy before is zero so I figured that the kinetic energy of the 20.0kg piece would be the negative sum of the other two. it works algebraically and I figured because there is no outside forces acting on the system it should work. I believe that the energy of one piece must be proportional to the others. Im not too sure here though. anyways then to find the angle I treated the other two kinetic energys as vector components and added them to find a resultant vector and then since my 20.0kg piece is equal to the negative of the sum of the othger two energies. I figure that the direction would be the the negative of the direction of the other two if they were to be treated as vector componenets and added togther.