Block and tackle in the line that either attach to or run through the moving blocks—in other words, the number of supporting rope sections. An ideal block and tackle with a moving block supported by "n" rope sections has the mechanical advantage (MA), where F is the hauling (or input) force and F is the load. Consider the set of pulleys that form the moving block and the parts of the rope that support this block. If there are "n" of these parts of the rope supporting the load "F," then a force balance on the moving block shows that the tension in
Block and tackle 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. The decision of which to use depends on pragmatic considerations for the total ergonomics of working with a particular situation. Reeving to advantage is the most efficient use of equipment and resources. For example, if the load is to be hauled parallel to the ground, reeving to advantage enables the pulling force to be in the direction of the load movement, allowing obstacles to be managed more easily. Reeving to disadvantage adds an extra