Simple Machines and Mechanical Advantage

All complex machines are made from combinations of six simple machines. A lever is a rigid bar that pivots on a fulcrum (pivot point), allowing you to lift heavy objects with less force. Examples: crowbar, seesaw, pry bar. A pulley is a wheel with a grooved rim for a rope or chain; it can redirect force and provide mechanical advantage. Examples: block and tackle, flagpole. An inclined plane is a sloped surface; it allows you to move heavy objects upward using less force than lifting straight up. Examples: ramp, ladder-like surface. A wedge is an inclined plane used to split or separate materials. Examples: ax, knife, chisel. A screw is an inclined plane wrapped around a cylinder; it converts rotational motion into linear motion. Examples: wood screw, drill bit, clamp. A wheel and axle is a wheel rotating on an axis; it reduces the force needed for rotation and allows movement. Examples: door handle, steering wheel, bicycle wheel.

The fundamental principle is mechanical advantage: if you use less force, you must move through a greater distance. A lever with a long arm lets you lift a car with small force, but you push the long arm down a greater distance. The work done is the same (force × distance), but the machine redistributes it to make the task easier. Understanding this principle explains why all simple machines work and helps you predict their behavior.