1. The problem statement, all variables and given/known data A disc of mass m is moving horizontally to the right with speed v on a table with neglibible friction when it collides with a second disc of mass 2m. The second disc is moving horizontally to the right with speed v/2 at the moment of impact. The two disc stick together upon impact. The speed of the body immediately after the collision is: A)v/3 B)v/2 C)2v/3 D)3v/2 E)2V 2. Relevant equations p = mv (that wasn't given, but that's the equation I used) 3. The attempt at a solution mv = mv + 2mv/2 m(v) = m(v+2v/2) v= v+2v/2 v= 2v/2 + 2v/2 for the final answer, I got: v= 2V, according to my answer sheet, the correct answer is 2v/3. I can't seem to figure out what I'm doing wrong. Please help.