WEDGE

A wedge is made of two inclined planes placed back-to-back. When you push a wedge forward, it forces material apart sideways. This allows a small forward force to create large separating forces.

Knives, axes, chisels, and even doorstops are all wedges. Instead of lifting or pulling material apart directly, wedges convert forward motion into splitting motion. The sharper the wedge, the easier it is to cut or separate.

Memory trick: Push forward → things move apart.