Carousel: when the ball flies off

What the experiment shows

A motor gradually spins up the disk. A ball near the edge moves on a bigger circle and faster — friction stops being enough and it flies off first.

How to run it

1. Press “Run” and watch the balls.
2. Change the disk’s friction — do the balls leave earlier or later?
3. Put a ball at the center: does it stay?

Questions to discuss

• Why does a carousel rider feel pushed outward?
• What holds the ball on the disk?

The science

To move in a circle a body needs a centripetal force F = m·ω²·r. Friction provides it. It grows with the radius, so near the edge friction runs out at a lower spin rate: μ·m·g = m·ω²·r → ω = √(μg/r).

Try it at home

Place coins at different distances from the center of a turntable or a swivel stool and spin it up.

What to change in the editor

• Change the motor speed.