AP physics 1, problem 6.32 part b

[Vivien]

Hello,

I think the solution for the part b has some problem. To calculate the new center of mass, the boy's new position should not be 4.24m as shown in the solution. While the boy walks across the raft, the raft is also moving. The other corner already shift towards the left. I believe the final position of the boy relative to the raft's center should be (x + 2.12) m. Using this in the CM calculation, x = -0.424 m. So the raft moved 2.544m in the direction opposite the boys's displacement.

Thanks for your attention.