Mechanical advantage device advantage for a screw can be calculated using the following equation: where Note that the actual mechanical advantage of a screw "system" is greater, as a screwdriver or other screw driving system has a mechanical advantage as well. Mechanical advantage device A simple machine that exhibits mechanical advantage is called a mechanical advantage device - e.g.: 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
Block (sailing) matter is slightly complicated by the fact that every tackle has a "working end" where the final run of rope leaves the last sheave. More mechanical advantage can be obtained if this end is attached to the moving load rather than the fixed end of the tackle. There are various types of blocks that are used in sailing. Some blocks are used to increase mechanical advantage and others are used simply to change the direction of a line. A "ratchet block" turns freely when a line is pulled in one direction but does not turn the other direction, although the