Which physical principle is used to calculate the mechanical advantage of a pulley system?

The mechanical advantage of a pulley system is calculated using the relationship between input and output forces. In a pulley system, the mechanical advantage indicates how much a machine amplifies force. It is defined as the ratio of the output force (the force exerted by the machine) to the input force (the force applied to the machine).

This principle is fundamental to understanding how a pulley can help lift heavy loads with less effort. For example, if a pulley system allows you to lift a 100-pound weight with only 50 pounds of force, the mechanical advantage is 2. This concept showcases the leverage a pulley offers by changing the direction of the force and distributing the load in a way that minimizes effort required by the user.

The other principles listed do not directly relate to calculating mechanical advantage in the context of a pulley. Conservation of momentum deals with the total momentum of a system of particles being constant in the absence of external forces. The principle of leverage, while relevant to machines in general, is a more broad principle that does not account specifically for the input-output force relationship in pulley systems. The law of inertia concerns the motion of objects at rest and in motion and does not directly influence the calculation of mechanical advantage either.