Three carts of masses m1 = 4.00 kg, m2 = 10.0 kg, and m3 = 3.00 kg move on a frictionless, horizontal track with speeds of v1 = 5.00 m/s to the right, v2 = 3.00 m/s to the right, and v3 = 4.00 m/s to the left as shown. velcro couplers make the carts stick together after colliding. find the final velocity of the train of three carts