A 45.0-kg woman stands up in a 60.0-kg canoe of length 5.00 m. She walks from a point 1.00 m from one end to a point 1.00 m from the other end. If you ignore resistance to motion of the canoe in the water, how far does the canoe move during this process? At first I thought that the canoe must move 3m in the opposit direction she walked along it since there was so fluid resistance. However, I decided the center of mass shifts so that the canoe should move the distance that center of mass shifted from one end to the other. My center of mass equation is: x_cm = (60kg * 5m/2)/(60kg + 45kg) = 1.429 So the center of mass in the canoe is 1.429 m from the tip of the canoe on the side that the woman is standing. Since she walks 3 m and ends up on the opposite side of the canoe in the exact same spot relative to the tip of the canoe, the center of mass has also shifted to 1.429m from that end. I added the two center of masses, and got 2.857m. I figured that subtracting that amount from the length of the canoe (5m) should give me the total distance moved by the canoe while she was walking, or 2.143m. This isn't correct, however. Does anyone know if I may have overlooked something?