Simple Pendulum
Swing a pendulum from a chosen length and starting angle — numerically integrated, so large swings behave correctly (not just the small-angle approximation).
Preview — sign up free to change the numbers yourself
What you can adjust
- Length
- 0.1 – 10 m
- Gravity (g)
- 1 – 25 m/s²
- Initial angle
- 1 – 170 °
Small angles (~<20°) swing at a nearly fixed period — push it past 90° and watch the period stretch out.
About this simulation
What it shows
A pendulum is released from rest at a chosen starting angle and swings back and forth without losing energy.
The key idea
For small swings the period is about 2π√(L/g): it depends on the length and gravity but not on the mass or the size of the swing. Big swings take longer than that formula says.
Try this
Set Length to 1 m and then 4 m: the swing takes twice as long, because the period grows with the square root of the length.
The motion is worked out step by step with the full equation, not the small-angle shortcut, so large starting angles are handled correctly. There is no friction.