A person of mass 60kg is standing on a small boat of mass 240kg that is initially at rest on a calm lake. The person jumps horizontally from the boat and lands on the shore with a speed of 3m/s relative to the ground. Consider the water resistance to be negligible for the short interval of the jump.
a. (a) Calculate the speed with which the boat starts moving immediately after the person jumps.
b. (b) A friend watching the event remarks, "The boat moves backward because the person pushes the boat backward and there is no equal and opposite force acting on the person." Analyse this remark and correct any misconception present, clearly relating your explanation to Newton’s Third Law.