Problem 66.

You are trying to cross a river that flows due south with a strong current. You start out in you motorboat on the west bank desiring to reach the east bank directly across from your starting point. Which direction should head your motorboat? Dram a picture of the river, the banks, and your motorboat, and include the relevant velocity vectors. What information would you need in order to determine the actual direction you need to head?

Solution:

To find the actual direction of the boat velocity we need to know the velocity of the river and the speed of the boat relative to the river (relative velocity). Then the actual velocity (this is the vector) is

The diagram is shown below.