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## Homework Statement

A massless spring of spring constant 20 N/m is placed between two carts. Cart 1 has a mass M1 = 5 kg and Cart 2 has a mass M2 = 3 kg. The carts are pushed toward one another until the spring is compressed a distance 1.3 m. The carts are then released and the spring pushes them apart. After the carts are free of the spring, what are their speeds?

## Homework Equations

conservation of energy

conservation of momentum

## The Attempt at a Solution

I have worked on this a bit but can't get the right answer...

I have a conservation of energy equation: .5Kx^2 = .5m1v1^2 + .5m2v2^2

and I also have a conservation of momentum one: Pi = Pf, 0 = m1v1 + m2v2

I tried solving for v1 and plugging it into the first eqn to get a velocity, but I can't seem to get it right...any ideas? Thanks!