Calculating Energy Loss in a Hockey Puck Collision

[hganser]

One hockey puck of mass 0.1 kg strikes an identical stationary puck on a frictionless ice rink. If the first puck had a velocity V(0)=3.8m/s before the collision and v(1)=0.8 m/s after in the same direction, what fraction of the energy was lost?
Where do I even start to find the answer??

 

[w3390]

If the rink is frictionless, then no energy should be lost. This is a momentum problem, and momentum is a conserved quantity. Is this your question, or are you trying to find the fraction of energy lost in the first puck as opposed to the fraction of energy lost of the system?

 

[dantose]

I would assume the question is asking how much energy was lost by the first puck.

That's a simple matter of taking the energy before and after via E=1/2mv²

The difference would be the energy lost by the first puck.

 

[w3390]

If you are indeed talking about the energy lost by the first puck then dantose is correct.