Final answer:
Simple machines are devices that can be used to multiply or augment a force that we apply - often at the expense of a distance. The mechanical advantage of a simple machine is the ratio of the output force to the input force. Examples of simple machines include levers, gears, pulleys, wedges, and screws.
Step-by-step explanation:
Simple machines are devices that can be used to multiply or augment a force that we apply - often at the expense of a distance through which we apply the force. Examples of simple machines include levers, gears, pulleys, wedges, and screws. The mechanical advantage of a simple machine is the ratio of the output force to the input force. It allows us to do work with less force by increasing the distance over which the force is applied. For example, a lever can be used to lift a heavy object by applying a smaller force over a longer distance on one side of the lever.