If someone is on a boat that rests in a placid river with negligible friction between the boat and the river ,, suppose that person moves a certain distance ,Does that boat move as well , if so why ?
so the boat will move the same x-displacement as the man in order to maintain the same center of mass of the system .Exactly. So, if the man moves a distance X closer to shore (say), how can you figure out how much the boat must move in order that the center of mass of the system stay put?
Of course. So?there is a problem here because if the boat moves, the man as well will move .
you mean if the man moves towards the right , so he is getting closer to the shore, the boat will move in the opposite direction (to the left ).Of course. So?
If the boat moves a certain distance to the left, how far must the man move? (Note that if you measure the man's movement with respect to the boat, then you have to add the movement of the boat to find his movement with respect to the shore.)