Velocity After Collision Hello everyone! I am new to these forums, and it looks like they are a great place to learn and ask questions!!! I have been given an assignment to do and there are a few questions that I can't get, if anyone could help me I would really appreciate their efforts. Oh, and sorry for posting in the wrong forum the first time! #1 (A) A 15.0 kg object is moving east at a velocity of 7.0 m/s when it collides with a 10.0 kg stationary object. After collision the 15.0 kg object is travelling at a velocity of 4.2 m/s at 340 degrees. What is the velocity of the 10.0 kg object after the collision? I listed all of my givens but still can't seem to find an answer. By the way the answer to the question is 5.1 m/s at 25 degrees. (B) Is this an elastic or inelastic collsion. Provide mathematical evidence for your answer. I know that this is an inelastic collision because the kinetic energy will change and be lost as heat, sound, and light energy. But how do I prove it mathematically? The answer is 1.1 x 10^2 J . I was going to use the equation Ek= (1/2)m(v^2), but as I can't figure out part A it isn't helping me much. If anyone can help me I would really appreciate it the effort!