Wheel and axle

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Gears, an example of a wheel and axle
Gears, an example of a wheel and axle

The wheel and axle is a simple machine. It consists of a wheel that turns an axle, or an axle that turns a wheel. It is also a lever that turns in circles around a point or fulcrum. The load on the axle is more easily moved because of mechanical advantage. The wheel and axle can be considered to be a lever in which the radius of the wheel is the effort arm and the radius of the axle represents the resistance arm. It also is a single forced machine. By changing the short distance of lifting, the force is less because the work always stays the same.

One of the most common wheel and axles is the wheel of a car or truck. On most of these, the wheel and axle acts as a lever rotating around the fulcrum or the center point. On doing this the wheel rolls.

A wheel and axle is made up of a several parts. A rod, which is the axle, is stuck rigidly to a wheel so that when the rod attached the wheel rotates the wheel would also turn.

Screwdrivers, doorknobs, windmills, gears, and Chain Falls are all examples of the wheel and axle.

[edit] Calculating Mechanical Advantage

[edit] Ideal Mechanical Advantage

The ideal mechanical advantage of a wheel and axle is calculated with the following formula:

IMA = \frac {D_E} {D_R}

The effort distance is the radius, diameter, or circumference of whichever part of the simple machine, wheel or axle, is initally being rotated. The resistance distance is the same measurement of the opposite part of the wheel and axle. For example, if the axle is initially rotated and the wheel is rotated by the axle then the axle is the effort distance and the wheel would be the resistance distance.

[edit] Actual Mechanical Advantage

The actual mechanical advantage of a wheel and axle is calculated with the following formula:

AMA = \frac {R} {E_{actual}}
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