1. The problem statement, all variables and given/known data Two carts with masses m1 = 0.8 kg and m2 = 1.2 kg are moving toward each other with speeds v1 = 4.5 m/s and v2 = 3.8 m/s as shown in the diagram below. The two carts collide elastically. Some reason I'm getting too high of a value, dont know I'm doing wrong... 2. Relevant equations momentum = m1v1 + m2v2 = m1vf1 + m2vf2 kinetic energy = .5m1v1^2 + .5m2v2^2 = .5m1vf^2 + .5 m1vf2^2 3. The attempt at a solution So I found the momentum which came out to be -.96 = .8vf1 + 1.2vf2 Rearranged the equation to solve for vf2 = -(2/3)vf1 - .8 Then tried to find kinetic energy and got 8.1 + 10.83 = .4vf1^2 + .6vf2^2 Plugged in v2 and got 16.76 = .4vf1^2 + (4/15)vf1^2 + .64vf1 + .384 Subtracted 16.76 from both sides Used quadratic equation Came out with 13.5 m/s for vf1.