A train is moving slowly eastward at 4m/s. A child in the train has sent his robot walking at 1.2 m/s from the left side to the right side of the train, which is 3m wide.
a) What is the velocity (magnitude and direction) of the robot with respect to the ground?
b) How long does it take the robot to move across the train?
c) What is the displacement of the robot with respect to the ground?