A 46.2 kg girl is standing on a 132 kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.22 m/s relative to the plank.
What is her velocity relative to the ice surface?
What is the velocity of the plank relative to the ice surface?