1. The problem statement, all variables and given/known data A 3.0 kg cart moving to the right with a speed of 1.0 m/s has a head-on collision with a 5.0 kg cart that is initially moving to the left with a speed of 2.0 m/s. After the collision, the 3.0 kg cart is moving to the left with a speed of 1.0 m/s. What is the final velocity of the 5.0 kg cart? 2. Relevant equations P=mv 3. The attempt at a solution I took the initial momentum of both cars and added them for the total initial momentum which was 3⋅1+5⋅2 = 13 kg m/s so because of the conservation of momentum Pf=Po so the final total momentum will have to be 13 kg m/s also. so Pftotal = Pcar 1 + Pcar 2 car 1 is now moving to the left with a velocity of 1m/s so its momentum is still 3 kg m/s so 13=3+Pcar 2 and we know the mass of car 2 is 5kg so 13=3+2⋅V and we see the momentum of car 2 would have to be 10 kg m/s to result in a final total momentum of 13kg m/s so wouldn't the velocity have to be 2m/s ?? but on the answer sheet it says the final velocity is 0.8m/s to the left.