Hockey Puck Collision--momentum problem

[mtruong1999]

Homework Statement

The problem reads:
"Hockey puck A sliding on ice with velocity 10 m/s in the x direction collides at a glancing blow with a second stationary puck B. Puck A scatters at an angle of θ_A= 40 degrees above the x axis, while B slides away at an angle ofθ_B= 50 degrees below the x axis. (a) Use momentum conservation to find the final speeds v_A and v_B of the two pucks, respectively. What is the change in kinetic energy? (b) What are the two scattering angles according to an observer in the center of mass frame of reference?"

Homework Equations

m_Av_1A + m_Bv_1B = m_Av_2A + m_Bv_2B

The Attempt at a Solution

Ok, so far I divided the problem into x and y components, where the final velocities in the x direction would be v_2Acos40 and v_2Bcos50 and the final velocities in the y direction would be v_2Asin40 and -v_2Bsin50. I feel like there are too many unknowns, we aren't given the masses of the two pucks, and I have absolutely no clue how to do this problem without the masses of the pucks. I have 4 unknowns (final velocities and the masses) and only two equations. Am I missing something? How do I approach this problem??

 

[TSny]

Assume the pucks have equal mass.

 

[mtruong1999]

Assume the pucks have equal mass.

Then the masses will cancel out?? BRILLIANT, that makes a lot of sense, thank you!