A girl of mass mG is standing on a plank of mass mP. Both areoriginally at rest on a frozen lake that constitutes africtionless, flat surface. The girl begins to walk along the plankat a constant velocity vGP to the right relative to the plank. (Thesubscript GP denotes the girl relative to the plank.)
(a) What is the velocity vPI of the plank relative to thesurface of the ice? (Use the following as necessary: vGP, mG, andmP. Indicate the direction with the sign of your answer. Let thepositive direction be in the direction that the girl walks.)
vPI =
(b) What is the girl's velocity vGI relative to the ice surface?(Use the following as necessary: vGP, mG, and mP. Indicate thedirection with the sign of your answer. Let the positive directionbe in the direction that the girl walks.)
vGI =
