How Do You Gain A Mechanical Advantage With Pulleys?
Mechanical advantage is the ratio of force output by a machine to the force input. In the case of a pulley system, the force output is made greater than the force input by doubling up the line. In other words, it magnifies force. The trade off for less input force needed is that more line needs to be pulled out to lift a load the same distance. As with a lever, the force times the length over which the force is applied stays constant, so the energy in equals the energy out (not accounting for loss from friction). Purchase two double-pulley blocks (see Resources section). Attach one of the blocks to the load to be lifted. The block will have two eyelets. Affix the load to the block through one of these eyelets. Hang the other block to a support above the load, again using one of the two eyelets. Thread end A of the line you are using through one of the two wheels of the hanging block. Specifically, it will fit into the groove of the wheel, making contact only with the top half of the wh
