Drag

The v² law

An interactive lesson with 6 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

• Drag $F_D = \tfrac12 \rho v^2 C_D A$: it grows as $v^2$.
• The power needed against drag grows as $v^3$.
• Streamlined shapes (low C_D) and small frontal areas cut drag.

Steps

1. The drag equation
2. Faster on the motorway
3. Power against drag
4. A car at speed
5. Terminal velocity
6. Twice as fast