1. The problem statement, all variables and given/known data a .450kg ice puck moving east with a speed of 3 m/s has a head on collision with a .9 kg puck initially at rest. Assuming a perfectly elastic collision what will be the speed and direction of each object after the collision? 2. Relevant equations v1 +v1f = v2+v2f m1*v1+m2*v2=m1*v1f+m2*v2f .5*m1*v1i^2 + .5*m2*v2i^2 = .5*m1*v1f^2 + >5*m2*v2f^2 3. The attempt at a solution I've used the first equation listed and rearranged it for V2f in order to solve for V1f, and plugged that back into the second equation without luck. I've googled the solution to elastic collisions but that only confuses me more. Which equation am I supposed to plug this into? Once i have V1f can i use the first equation to solve for V2f, or do i need to go through the whole process again? It's a bit of algebra so i may have gotten lost somewhere in there. COuld someone just give me a play by play of what i'm supposed to do here to do this the short way, as I know the long way is using the 2nd and 3rd equations and thats WAY more algebra. All help is appreciated! Thanks in advance!