Physical

There is o 720 kg go-kart that travels at 3 m/'s to the right while an oncoming 600 kg cart moves to the left with 7 m/'s velocity. After a perfectly elastic collision where kinetic energy is conserved, what are the 2 new speeds of each? Label the 720 kg cart "A" and the 600 kg cart "B" 16. Cart A's new speed after the collision is (include correct sign, +/-) 17. Cart B's new speed after the collision is (include correct sign, +/-)