Part 1

A 36 kg girl is standing on a 65 kg plank. The
plank, originally at rest, is free to slide on a
frozen lake, which is a ﬂat, frictionless supporting surface. The girl begins to walk along the plank at a constant speed of 1.89 m/s to
the right relative to the plank.
What is her velocity relative to the ice surface?
Answer in units of m/s

Part 2
the plank at a constant speed of 1.89 m/s to
the right relative to the plank.
What is her velocity relative to the ice surface?
Answer in units of m/s