Relative Motion

It depends who’s watching

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

• Velocities are measured relative to a frame of reference.
• Relative velocities add as vectors (at everyday speeds).
• To cross a river straight, aim upstream so the current is cancelled.

Steps

1. Frames of reference
2. Head-on
3. Crossing the river
4. Time to cross
5. Slanting rain
6. Flying in wind