5 pt A railroad cart with a mass of m = 13.4 t is at rest at the top of an h = 11.8 m high hump yard hill. m m, h After it is pushed very slowly over the edge, it starts to roll down. At the bottom it hits another cart originally at rest with a mass of m = 17.0 t. The bumper mechanism locks the two carts together. What is the final common speed of the two carts? (Neglect losses due to rolling friction of the carts. The letter t stands for metric ton in the SI system.) (in m/s)