How do gears affect rotational speed?

Gears play a crucial role in mechanical systems by controlling the rotational speed through their size and the ratio between the gears interacting with each other. When two gears are engaged, the speed at which one gear turns can affect the speed of the other through the gear ratio.

If one gear, known as the driving gear, has more teeth than the second gear, the driven gear, it will turn slower while the second gear, having fewer teeth, will turn faster. Conversely, if the driving gear has fewer teeth than the driven gear, the driving gear will turn faster while the driven gear turns slower. This relationship allows for both increasing and decreasing the rotational speed depending on the arrangement and sizes of the gears.

In mechanical systems, this function is essential for achieving desired outcomes, whether that be increasing torque for a specific application or achieving a higher rotational speed. Hence, the correct answer highlights that gears significantly modulate rotational speed based on their dimensions and the ratio between them.