Students will learn how analyze and solve problems in two dimensions containing velocity vectors but no acceleration.
Key Equations
Example 1
Question: If a river is flowing north at 2 m/s and you swim straight across (i.e. east) at 1.5 m/s, how far up shore will you be from your starting point once you reach the other side? The river is 9 m wide.
Answer: First solve for the time it takes you to reach the other side. Let's let north be the ydirection and the direction across the river be the xdirection.
thus,
Now, use the time you are in the water to find how far the river has carried you north.
Watch this Explanation
Simulation
Explore More
 If a river is flowing south at 4 m/s and you swim straight across (i.e. east) at 2 m/s; admittedly, you're going to drift a bit south. That said, calculate that distance that you drifted south from your starting point. The river is 16 m wide.
 If a river is flowing south at 3 m/s and you swim at an angle of 30 degrees north of directly east at 1 m/s, how far did you drift up or down stream from your starting point once you reach the other side? The river is 10 m wide.
 If a river is flowing north at 2 m/s and you can swim at 4 m/s, what angle should you swim at such that you arrive directly across the river (i.e. no drift north or south from starting point on other side)? The river is 10 m wide.
 If a river is flowing south at 5 m/s and you can swim at 4 m/s maximum, is it possible to arrive directly across? Why or why not?
Answers to Selected Problems

32m 
28.9m south of starting point 
30 degrees  No, even if you swim directly north the river will still take you south at 1 m/s