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AEM
#2
Apr26-10, 08:52 PM
PF Gold
P: 362
The essence of this problem is that since all forces involved are internal to the system, the center of mass of the system (plank plus girl) does not move even though the girl and the plank do move. The velocity of the girl or the plank is immaterial, {though as a practical matter, she should move slowly :) }