posted by kaleb .
A sunbather lying on a floating raft that experiences no friction with the water gets up and walks to the western end of the raft. While she is walking, how does the center of gravity of the system composed of her and the raft move? Why? If the mass of the raft is 10 times that of the sunbather's mass, in which direction and about how fast does the raft move in terms of the sunbather's speed?
consider a sytem comprising of Sunbather + raft.
No external force on this system.Therefore thr Center of mass of the system will remain stationary. If she walks to the west, the raft will move to the east by a distance that will keep the CM at the original location.
No external force also means that linear momentum will not change.
Ms*Vs = - Mr*Vr
Vr = - Ms*Vs/Mr = - Ms*Vs/10*Vs
Vr = - Vs/10