How is the mechanical advantage of a pulley system determined?

The mechanical advantage of a pulley system is determined by the number of supporting ropes or strands. This concept stems from the fundamental principle of how pulleys distribute weight through multiple ropes, effectively reducing the force required to lift an object. Each additional rope or strand that supports the load allows the force needed to lift the weight to decrease. This means that if a pulley system has more supporting strands, the mechanical advantage increases, allowing a smaller effort to lift a larger weight.

The options that are not correct focus on aspects that do not directly influence mechanical advantage. The length of the rope does not affect the mechanical advantage; it can impact factors such as the distance the load moves, but not the force required to lift it. The weight of the object being lifted is a factor in calculating the force needed but does not indicate how many strands are used in the system. Similarly, the diameter of the pulley wheel influences the effort applied due to friction and can change the efficiency of the system, but it doesn't affect the mechanical advantage derived from the number of supporting ropes.