Elastic collision speed and time problem

[fizzzzzzzzzzzy]

A 0.45 kg ice puck, moving east with a speed of 3 m/s, has a head-on collision with a 0.9 kg ice puck. Assuming a perfectly elastic collision, what will be the speed and direction of each object?

Alright, so the first time i go through this problem i solve it, no problem. the answer is 1 m/s west and 2 m/s east and that's also the answer in the book. but then i go back and i realize something weird. i set up the momentum equation like normal so that it's
0.45*3 = 0.9v1 + 0.45 v2
and then you can make it
0.45*3 = 0.45*2v1 + 0.45 v2
divide both sides by 0.45
3 = 2v1 + v2
and you get that but the values determined for the speeds don't match up with that. What's going on?

 

[learningphysics]

A 0.45 kg ice puck, moving east with a speed of 3 m/s, has a head-on collision with a 0.9 kg ice puck. Assuming a perfectly elastic collision, what will be the speed and direction of each object?

Alright, so the first time i go through this problem i solve it, no problem. the answer is 1 m/s west and 2 m/s east and that's also the answer in the book. but then i go back and i realize something weird. i set up the momentum equation like normal so that it's
0.45*3 = 0.9v1 + 0.45 v2
and then you can make it
0.45*3 = 0.45*2v1 + 0.45 v2
divide both sides by 0.45
3 = 2v1 + v2
and you get that but the values determined for the speeds don't match up with that. What's going on?

they match. If v1 is 2m/s east and v2 is 1m/s west... v1 = 2. v2 =-1.

3 = 2(2) + (-1)

 

[m2003]

It is possible that there is a mistake in the calculation or in the values used in the equation. It is important to double check all calculations and make sure that the correct values are being used in the equation. Additionally, it is important to consider the direction of the velocities and make sure they are correctly represented in the equation. If the problem still persists, it may be helpful to consult a peer or instructor for assistance in solving the problem.