The Big Three

Equations for constant acceleration

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• $v = v_0 + at$, $\;\Delta x = v_0 t + \tfrac12 at^2$, $\;v^2 = v_0^2 + 2a\Delta x$, for constant acceleration only.
• Braking distance is $v_0^2 / (2|a|)$: double the speed means four times the distance.
• Pick the equation that leaves out the quantity you don’t know.

Steps

1. From rest
2. Two equations from one graph
3. The time-free equation
4. Braking distance
5. Emergency stop
6. Runway
7. Take-off time