1. The problem statement, all variables and given/known data
I am copying this problem from my textbook. It is about momentum and Kinetic energy

3. The attempt at a solution

My problem lies in part B. According to Part A, v₁'=v₁‐kv₂'
But in part B, (v₁‐kv₂')²+kv₂'²=v₁'², see the problem? v₁‐kv₂' has been plugged into v₁'² and it reappeared again on the right hand side.

Right I need help. KEEP IN MIND THAT "K" IS THE RATIO OF M_{2}/M_{1}
ALSO[/SIZE] PLEASE SHOW ME HOW TO GET TO PART C

Yes, you're right, I need glasses. It has to be unprimed on the right side. Sounds like a typo (prime's are easy to mess up :rofl:). The jump to part C makes sense now.

It's a momentum question. Basically it states an object with velocity collides a stationary object that is heavier than the object clashing in. The result is both objects repelling and heading the opposite direction of each other. I am suppose to find the velocity using the conversation of energy - KE.

So k=m2/m1. Part C shows you exactly what v2' is so you should be able to solve for it immediately with no tricks or substitutions other then k=m2/m1. To solve for v1', use the very first equation you have after you solve v2'.

You were correct in noticing it was a typo in the third and subsequently 4th line. The [tex]v_1 '^{^2 } [/tex] should have been a [tex]v_1 ^2 [/tex] on the right side. The line after it is also incorrect. You have the right idea to plug in v1' from the first equation. Now expand the left side and its a simple cancellation. Subtract [tex]v_1 ^2 [/tex] from both sides and you get part C and you can solve for v2' immediately.