A 45.0 kilogram schoolgirl is standing on a 135 kilogram plank. The plank is 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 fix velocity of 1.52 m/s relative to the plank.
(a) Compute her velocity relative to the surface of ice?
(b) Compute the velocity of the plank relative to the surface of ice?