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Wheelchair ramp, Hotel Montescot, Chartres, France Demonstration inclined plane used in education, Museo Galileo, Florence.. An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle from the vertical direction, with one end higher than the other, used as an aid for raising or lowering a load.
Engraving from an 1824 mechanics magazine illustrating Archimedes's statement that given a place to stand, with a lever a person could move the Earth. The idea of a simple machine originated with the Greek philosopher Archimedes around the 3rd century BC, who studied the Archimedean simple machines: lever, pulley, and screw.
The lever is operated by applying an input force F A at a point A located by the coordinate vector r A on the bar. The lever then exerts an output force F B at the point B located by r B. The rotation of the lever about the fulcrum P is defined by the rotation angle θ in radians. Archimedes lever, Engraving from Mechanics Magazine, published ...
Wheel and axle motion (e.g. screwdrivers, doorknobs): A wheel is essentially a lever with one arm the distance between the axle and the outer point of the wheel, and the other the radius of the axle. Typically this is a fairly large difference, leading to a proportionately large mechanical advantage.
Ramps have been reported as being widely used in Ancient Egypt. A ramp is an inclined plane, or a plane surface set at an angle (other than a right angle) against a horizontal surface. The inclined plane permits one to overcome a large resistance by applying a relatively small force through a longer distance than the load is to be raised.
The lever is a movable bar that pivots on a fulcrum attached to or positioned on or across a fixed point. The lever operates by applying forces at different distances from the fulcrum, or pivot. The location of the fulcrum determines a lever's class. Where a lever rotates continuously, it functions as a rotary second-class lever.
The force on a screw is not usually applied at the rim as assumed above. It is often applied by some form of lever; for example a bolt is turned by a wrench whose handle functions as a lever. The mechanical advantage in this case can be calculated by using the length of the lever arm for r in the above equation.
A lever arm uses the fulcrum to lift the load using and intensifying an applied force.In practice, conditions may prevent the use of a single lever to accomplish the desired result, [1] e.g., a restricted space, the inconvenient location of the point of delivery of the resultant force, or the prohibitive length of the lever arm needed.