How do gears operate as simple machines?

Gears operate as simple machines primarily by transmitting force through interlocking teeth. The design of gears allows them to work together effectively; when one gear turns, its interlocking teeth push against the teeth of another gear, causing it to rotate as well. This mechanism is essential for transferring rotational motion and force from one part of a machine to another.

The effectiveness of gears is especially evident in applications where increased torque is necessary or when altering the speed of rotation is required. For example, smaller gears can drive larger gears, increasing torque and reducing speed, which is commonly used in vehicles and machinery.

Other options reflect concepts related to simple machines but do not accurately describe the function of gears. Gears do not enable linear motion through pulleys, as that describes a different type of simple machine. They also do not primarily rely on gravity for movement, which is more characteristic of inclined planes or levers. Additionally, while gears can help to minimize friction to some extent, their primary role is not to reduce friction but to effectively transfer motion and force.