Complex machines are two or more simple machines working together.
A wheelbarrow is an example of a complex machine that uses a lever and a wheel and axle. Machines of all types make work easier by changing the size or direction of an applied force. An inclined plane is a slanted surface used to raise an object. A ramp is an inclined plane. When an object is moved up an inclined plane, less effort is needed than if you were to lift it straight up, but, you must move the object over a greater distance.