Inclined Plane
Inclined Plane, a simple machine consisting of a flat, tilted surface. A ramp is an example. Two other simple machines—the screw and the wedge—work on the principle of the inclined plane. The screw can be regarded as a cylinder with an inclined plane wrapped around it and the wedge as two inclined planes placed back to back.
It requires less force to move an object up an inclined plane than it does to lift the object vertically. The object, however, has to be moved a proportionately greater distance, and the amount of work done therefore remains the same. (Work is calculated by multiplying force times distance.)
The theoretical mechanical advantage of an inclined plane (the number of times it multiplies force) is the length of the plane divided by its height (if, as in the illustration, force is applied parallel to the plane); or the length of the base divided by the height of the plane (if force is applied parallel to the base).
The ratio of height to length is called the grade of the inclined plane, and is expressed as a percentage. For example, an inclined plane 200 feet (61 m) long that rises 20 feet (6.1 m) would have a grade of 10 per cent.