1. The problem statement, all variables and given/known data Two air track gliders of a mass 300 g and 200 g are moving towards each other in opposite directions with speeds of 50 cm/s and 100cm/s respectively. Take the direction of the more massive glider as positive. A.) determine the velocity of each glider after the collision if the collision is elastic. 2. Relevant equations m1v1i +m2v2i = m1v1f + m2v2f quoted by "collinsmark" - "You have enough information to solve it (given that this is a 1 dimensional problem -- things can get more complicated if the objects can freely move in more than 1 dimension)." "You have the conservation of momentum equation that you listed above. But since you are assuming it is a perfectly elastic collision, you can also use conservation of kinetic energy (conservation of kinetic energy only applies if the collision is perfectly elastic). So you have 2 equations and 2 unknowns, which is solvable." 3. The attempt at a solution I know collinsmark was right in what he is saying but i don't undrstand what formuals to use to get the seperate velocites. Like this? 3(0.50) + 0.2(-1.00) = 0.3v1f 3(0.50) + 0.2(-1.00) = 0.2v2f then solve for the seperate velocites in each case? or just m1v1i = m1v1f so the velocity doesnt change only in direction. any help is greatly appreciated.