Wheel and axle.html

A well known application of the wheel and axle.

The wheel and axle is a simple machine. \By considering the machine as a torque multiplier, ie the output is a torque, items such as gears and screwdrivers can fall within this category.

1 Calculating mechanical advantage
- 1.1 Ideal mechanical advantage
- 1.2 Actual mechanical advantage
2 Examples
3 See also

Calculating mechanical advantage

Ideal mechanical advantage

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

$M.A.= \frac {Radius_{Wheel}} {Radius_{Axle}}$

The effort distance is the radius, diameter, or circumference of whichever part of the simple machine, wheel or axle, is initially 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.

The oldest wheel was found in Mesopotamia and is believed to be over 5,500 years old.

Actual mechanical advantage

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

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

where

R = resistance force, i.e. the weight of the bucket in this example.

E_actual = actual effort force, the force required to turn the wheel.

Examples

Doorknobs are similar to the water well, as the mechanism uses the axle as a pinion to withdraw the latch.
With a simple chain fall, the user pulls on the wheel using the input chain, so the input motion is actually linear.
Screwdrivers - an example of the rotational form. The diameter of the handle gives a mechanical advantage.
Gears

Wheel and axle.html

Contents

Calculating mechanical advantage

Ideal mechanical advantage

Actual mechanical advantage

Examples

See also