Circular Motion

Going in a circle needs a force pulling INWARD: Fc = m · v² / r

Change the speed v, radius r and mass m — watch a = v²/r and Fc = m·v²/r update live. The force always points to the centre.

Speed v

4 m/s

Radius r

2 m

Mass m

2 kg

a = v²/r = 4²/2 = 8 m/s²Fc = m·a = 2 × 8 = 16 N

The dot orbits; the arrow (the force) always points to the centre.

Force → to the centre

Remove the force and it flies off straight along the tangent — it does NOT curve.