EngQuest 2010

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Inclined Planes

An inclined plane is a flat surface that is at an angle to the load. This type of 'machine' has no parts that move.

An example of an inclined plane is a ramp for wheelchairs (see Diagram 3). The inclined plane of the ramp makes it easier for the person in the wheelchair to move up into a building. The load (the weight of the person in the wheelchair) can be moved up the ramp into the building against the force of gravity using a smaller effort (or force) than would be required to lift the person and the wheelchair the same height.

For example, the ramp needed to raise the wheelchair 1 metre higher might be 10 metres long, so the wheelchair needs to move 10 metres up the ramp in order to raise its height by 1 metre. In trading force for distance, the force pushing it up the slope needs to happen for 10 times the distance that the person in the wheelchair is raised. This gives a mechanical advantage of 10 (the distance travelled divided by the height gained).

The steeper the slope of the inclined plane, the more effort it takes to move the person in the wheelchair up the slope. The steeper slope in Diagram 3 is only 5 metres long. This gives the person in the wheelchair a mechanical advantage of only 5 and it therefore requires twice the effort to climb the same height.

Some other examples of inclined planes include roads leading up slopes, car ramps in parking stations, and even staircases for people to walk up and down. You will agree that it is easier to walk up a ramp or a staircase than to climb to the same height up a ladder.

Likewise, inclined planes can be used to work with gravity as objects roll down them. Did you notice how the inclined planes work with gravity to make the compound machine operate in the Simple Machines Animation? How many examples of inclined planes did you find?