Learn about Lever Machines in this educational video from dizzo95.
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Male Speaker: In order to get leverage, a lever must have a fulcrum. How much leverage can be gained depends on the length of the lever, where the fulcrum is placed, where force or effort is applied and finally where the load is positioned. There are three basic arrangements that will yield different kinds of leverage. In one case, the force and the load are on opposite sides of the fulcrum. When the applied force on the load already go distances from the fulcrum, the force applied will equal before as to the load, no leverage advantage is gained. But if the fulcrum is moved so that where the forces applied is twice the distance from the fulcrum than the load, only half the effort will be needed to move the load. Leverage will increase proportionally by shifting the fulcrum closer to the load. This proportion is called mechanical advantage. An example of this lever arrangement is the gripping capacity of pair of players and the powerful leverage of a pry bar. In another case, the load lies between the fulcrum and the point of effort. The closer the load is to the fulcrum, the greater the mechanical advantage. Again, the same rules are proportion or at work. If the effort applied is three times farther from the fulcrum than the load, the amount of effort needed to move the load is reduced to a third. This lever form is found in a wheel barrow and a nutcracker. In the third case, the force is applied between the load and fulcrum, very different from the first two cases. This type of leverage is not multiplied force, but instead multiplies motion. The load experiences less force than the effort, but moves proportionately greater distance as with a fishing rod pulling a fish or a pair of tweezers grasping an object. For all of these levers, what is gained in motion is lost in force. The larger force always moves through the smaller distance.

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