Mechanical advantage refers to the amplification of force and can be quantified as the ratio of the output force generated by a system to the input force applied to it. It is useful for a wide range of applications, like lifting heavy loads.
MECHANICAL ADVANTAGE
$$MA = \frac{F_{\mathrm{out}}}{F_{\mathrm{in}}}$$
The video below explores different methods that can be use to amplify a force, with a focus on levers, pulleys and gears, three types of machine that generate mechanical advantage.