hey, just need help on this question. i know the answer but i need all the working out as i have a test tommorrow and dont understand how and when to use the equations of motion and change in momentum etc. A 3.0kg mass moving at 4.0ms at 135degress collides with a 4.0kg mass moving at 2.0ms at 315 degrees. The collision occurs over 0.20s and the 3.0kg mass is measured to be moving off at 1.0ms at 135 degrees. Find: a) the final velocity of the 4.0kg mass b) the acceleration of the 3.0kg mass c) The force acting on each mass. Thanks a lot people!