What is a cog?

A cog is a mechanical device that transfers rotary motion from a shaft to another rotating object. It is typically a toothed wheel that works in conjunction with another cog to transmit power and perform a specific function, such as reducing or increasing speed, changing direction, or transmitting torque. Cogs are commonly used in various machines, including clocks, bicycles, automobiles, and industrial equipment. The number and size of cogs in a system determine the mechanical advantage and gear ratio. The teeth on the cogs are usually precisely designed and manufactured to ensure efficient and smooth transmission of motion and power.