Flow Lines

Following the arrows

An interactive lesson with 5 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• A flow line follows the arrows: dx/dt = P, dy/dt = Q.
• Flow lines never cross except at zeros of the field.
• Finding flow lines means solving differential equations.

Steps

1. A stream around a post
2. Circular flow
3. Hit the target
4. Can they cross?
5. Spreading out