A knife blade is an example of a wedge , which is one of the six basic simple machines.

What kind of simple machine is a knife blade?

  • A knife blade is shaped like a thin triangle that pushes material apart as it moves forward, which is exactly how a wedge works.
  • When you press down on the handle, the force is concentrated along the sharp edge, allowing the blade to split or cut objects more easily.

Why it’s a wedge (not just an inclined plane)

  • A wedge is essentially two inclined planes joined together and used to separate or split materials, rather than to move objects smoothly up a slope.
  • Tools like axes, chisels, and knife blades are classic wedge examples because they use a sharp edge to drive between particles of the material and force them apart.

TL;DR: A knife blade is a wedge type of simple machine because its sharpened, triangular shape concentrates force along a narrow edge to cut or split materials.