Wheel
A wheel and axle is a simple machine that consists of a circular object, the wheel, connected to a fixed rod, the axle. The wheel rotates around an axis and is used to transmit or transform linear or rotational motion and force. It is used to reduce friction and make movement easier.
Axle
In a wheel and axle system, the axle allows the wheel to rotate smoothly and efficiently, reducing friction and making it easier to move heavy loads. The axle also provides stability and support for the wheel.