1. The problem statement, all variables and given/known data This is collision in 2D problem. I already did most of the work except I'm stuck on the trigonometry and algebra for solving for the final velocity of object a. I will put the problem here just in case someone wants to show me a better way for getting to the answer. Collision between two pucks. Puck "a" has mass = 0.025kg Velocity of "a" = +5.5m/s along x axis "a" makes collision with puck "b" which has mass = 0.050kg and "b" starts at rest. Collision is not head on. So, after collision puck "a" flies apart from "b" at angle 65° and puck "b" flies off at angle 37° 2. Relevant equations I am trying to solve for Vfa; Ma*Voa = Ma*Vfa(cos65) + [Ma*Vfa(sin65)/(sin37)](cos37) Ma = X Voa = Y Vfa = Z XY = XZ(cos65) + [ XZ(sin65)/(sin37)](cos37) solve for Z Hopefully that's better. The solutions in textbook managed to solve for Vfa or Z like this: Z = Y/[cos65 + (sin65/tan37)] My question how to get Z by itself and where did (sin65/tan37) come from?