A 540- kg,10-m-long boat is placed perpendicular to a dock. When a 60-kg boy starts walking from the end to the front of the boat, the front of the boat touches the dock. The boy's distance from the dock when the boy reaches the front of the boat is
A) 0.0 m.
B) 0.50 m.
C) 1.0 m.
D) 4.5 m.
E) 5.5 m.

Question

Quizplus · Accepted Answer

The center of mass of the system (boat + boy) does not change as there are no external horizontal forces. Initially, the center of mass is at the midpoint of the boat. As the boy walks, the boat moves backward. When the boy reaches the front, the boat has moved such that the boy is 1.0 m from the dock.

A 540- Kg,10-M-Long Boat Is Placed Perpendicular to a Dock