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en:Image:Pulley phy wiki picture.JPG Public domain Public domain false false This work is ineligible for copyright and therefore in the public domain because it consists entirely of information that is common property and contains no original authorship .
Diagram 3 shows three rope parts supporting the load W, which means the tension in the rope is W/3. Thus, the mechanical advantage is three-to-one. By adding a pulley to the fixed block of a gun tackle the direction of the pulling force is reversed though the mechanical advantage remains the same, Diagram 3a. This is an example of the Luff tackle.
A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991–1802 BC) [1] and Mesopotamia in the early 2nd millennium BC. [2]
Printable version; In other projects Appearance. move to sidebar hide ... Description = Pulley diagram with 4 pulleys |Source = self-made |Date = 2006-09-02 ...
The typical configuration (see diagram) uses two single pulleys and two Prusik knot loops or other suitable friction hitches. [2] These Prusiks provide fixed attachment points on the rope that can be moved when slightly loosened. The first Prusik knot is attached to the "traveling pulley," allowing it to pull on the load.
Examples of rope and pulley systems illustrating mechanical advantage. Consider lifting a weight with rope and pulleys. A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a single pulley. It has a mechanical advantage (MA) = 1 (assuming frictionless bearings in the pulley ...
In sailing, a block is a single or multiple pulley. One or a number of sheaves are enclosed in an assembly between cheeks or chocks. In use, a block is fixed to the end of a line, to a spar, or to a surface. A line (rope) is reeved through the sheaves, and maybe through one or more matching blocks at some far end, to make up a tackle.
My recommendations: keep the lengths the same, adding pulleys each time and the depict weight rising successively higher off the ground.--HereToHelp 00:10, 25 March 2008 (UTC) More pulleys would not lift the weight higher, more pulleys would lift the weight less with the same amount of rope displacement (denoted s on the drawing).