Physics: Why Spin Cycles Remove Water, Not Clothes

Centripetal force is the net force that keeps an object moving in a circular path, directed toward the centre of rotation. For an object of mass m moving at speed v around a circle of radius r, this force is given by F = mv²/r. The equation shows that the required force grows with mass and with the square of speed, but falls as the radius increases — a relationship that explains why tight, fast turns demand much larger forces. Understanding what supplies this force matters, because centripetal force is not a new kind of force but a role filled by an existing one. In a spinning washing machine drum, the normal reaction from the inner wall pushes the clothing inward, perpendicular to the wall. Where the wall has holes, no such force can act on water droplets, so their inertia carries them in a straight line through the gaps — the mechanism behind the spin cycle.