A wheel and axle is a simple machine that consists of a circular wheel attached to a central rod called an axle. When the wheel turns, the axle turns with it, allowing for easier movement of heavy objects. This design reduces friction and makes it simpler to lift or transport loads. Common examples of the wheel and axle include bicycles, cars, and carts. In these applications, the wheel provides a larger surface area that rolls over the ground, while the axle connects the wheels and helps distribute the weight. This combination enhances efficiency in movement and transportation.