## finding final velocity in a perfectly elastic collision

~~~Two marbles with equal masses collide. Marble A has an initial velocity of 1.69 m/s while marble B is initially at rest. If marble A comes to rest as a result of the initial collision, what is the final velocity of marble B?

* Answers will be accepted if they are within 0.02 of the correct answer.

~Can anyone clarify this?
1. m1v1i + m2v2i = m1v1f + m2v2f

masses cancel....
2. v1i+v2i = v1f+v2f

3. (1.69m/s) + (0m/s) = (0m/s) + v2f

4. 1.69 m/s= v2f

I'm not sure this is correct...
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 Quote by ilovedeathcab ~~~Two marbles with equal masses collide. Marble A has an initial velocity of 1.69 m/s while marble B is initially at rest. If marble A comes to rest as a result of the initial collision, what is the final velocity of marble B? * DO NOT include units in your answer. * Give your answer with two decimals. * Answers will be accepted if they are within 0.02 of the correct answer. ~Can anyone clarify this? 1. m1v1i + m2v2i = m1v1f + m2v2f masses cancel.... 2. v1i+v2i = v1f+v2f 3. (1.69m/s) + (0m/s) = (0m/s) + v2f 4. 1.69 m/s= v2f I'm not sure this is correct...
Looks correct.
 thank you so much!!!