Question

A boat moves 3.0 km due north and then moves 1.0 km due south. The time for this trip is half an hour. What is the average velocity of the boat?

Answer 1

The total displacement

$$d=\rm 3\: km-1\: km=2\: km$$

The average velocity

$$v_{\rm ave}=\frac{d}{t}=\rm \frac{2\: km}{0.5\: hr}=4\: km /hr\; toward\; N$$