Which is the CORRECT formula for determining the mechanical advantage of the wheel and axle?

The formula for determining the mechanical advantage of a wheel and axle system is based on the relationship between the radii of the components involved. The mechanical advantage is expressed as the ratio of the radius of the crank (handle or lever attached to the wheel) to the radius of the axle (the central shaft around which the wheel revolves).

When you take the radius of the crank and divide it by the radius of the axle, you can determine how much easier it is to apply force using the wheel and axle compared to applying force directly at the axle. This ratio effectively tells you how many times the wheel amplifies the force exerted on the crank. The larger the crank radius relative to the axle radius, the greater the mechanical advantage, allowing for easier movement of heavier loads.

Understanding this concept is crucial when working with water and fuel systems that involve rotational components, as it helps in applying the right force and enhances the efficiency of the system. The other options do not reflect this specific and established relationship, making them unsuitable for calculating the mechanical advantage in a wheel and axle configuration.