Music boxes, toys, clocks, cars and tape players all have gears. The typical type of gear is a pinion gear however there are many other types of gears each of which meet the needs of certain applications. Torque and Speed Gears are used to perform mechanical work. A clock has two or three hands, each of which spin at different speeds but there is only one motor or power source turning the hands. The clock takes the speed of the input motor, gears it down and drives the second hand, gears it down again to drive the minute hand and down further to drive the hour hand.
Several gears allow one power source to drive a variety of objects.
When rotational speed is changed through gearing, the rotational force that can be applied also changes. Consider a car traveling on a highway, the car is in high gear traveling fast but with low acceleration ability. The transmission in a car transfers power from the engine to the drive train and moves the car. In rotational motion the formulas are identical, we just have some different terms. Rotational force is called Torque and rotational distance is measured in radians or degrees.