What is the purpose of a block and tackle pulley system?

The primary purpose of a block and tackle pulley system is to lift heavy loads with less effort by utilizing multiple pulleys. This system effectively reduces the amount of force required to lift an object by distributing the weight across several rope segments that work together. When multiple pulleys are employed, the mechanical advantage gained allows a user to lift heavier weights with significantly less input force, making tasks that involve lifting much more manageable.

While changing the direction of force is a function of a pulley system, this is not the exclusive benefit of a block and tackle. Increasing the speed of lifting or reducing friction are not the main functions of this type of pulley system either; rather, they focus primarily on making lifting easier. Thus, the correct answer highlights the significant mechanical benefit of using a block and tackle setup in practical applications.