A coal barge with a mass of 1,36 10* kg drifts along a river. When it passes under a coal hopper, it is loaded with 8.4 x 10 kg of coal. What is the speed of the unloaded barge if the barge after loading has a speed of 1,3 m/s? 3. A child jumps from a moving sled with a speed of 2.2 m/s and in the direction opposite the sled's motion. The sled continues to move in the forward direction, but with a new speed of 5,5 m/s. If the child has a mass of 38 kg and the sled has a mass 68 kg, what is the initial velocity of the sled? initial velocity of the sled would be 7.34 m/s 4. A swimmer with a mass of 58 kg and a velocity of 1.6 m/s to the north climbs onto a 142 kg raft. The combined velocity of the swimmer and raft is 0.32 m/s to the north. What is the raft's velocity before the swim- mer reaches it? 5. A 50.0 g shell fired from a 3.00 kg rifle has a speed of 400.0 m/s. With what speed does the rifle recoil in the opposite direction?