Gears and Pulleys

Gears

Gears are toothed wheels that interlock and transmit power, controlling speed, torque (force) and direction of rotation within mechanical systems.
Gears are classified in several types, including spur gears, which are simple and straight-toothed gears, and helical gears, which have teeth cut at angles, reducing noise and vibration.
Rack and pinion gears convert rotational movement to linear motion, common in steering systems of cars.
When two gears of differing sizes are connected, the smaller gear (often the driver) will turn more quickly than the larger gear (commonly the driven), this system is called a gear ratio.
Gear trains are used to achieve greater force or speed. This term refers to multiple gears working together, usually increasing the output speed or torque.
Bevel gears have teeth that are cut on an angle and are used to change the axis of rotation.
Gears also exemplify the principle of mechanical advantage, as they can amplify force or speed.

Pulleys

A pulley is a wheel that carries a flexible cable, cord, rope or belt around its rim, often used to lift heavy loads.
Fixed pulleys change the direction of force. Despite not providing a mechanical advantage, they make the work easier as one can pull downwards using the force of gravity.
Movable pulleys move along with the load providing a mechanical advantage of two or more, reducing the effort needed to lift a load.
Pulley systems or block and tackle, which use multiple pulleys, are employed to increase the mechanical advantage, conserving input energy and making lifting of heavy loads easier.
Much like gears and levers, pulleys demonstrate the principle of mechanical advantage by aiding in either amplifying force or making tasks easier to perform.

Remember, it’s important to practice drawing these mechanical systems and memorising how they function in real-life applications. Try to think of everyday examples to help solidify your understanding!