What role do pulleys play in simple machines?

Pulleys serve to redirect force, which allows a user to lift or move objects more efficiently. By changing the direction of the applied force, a pulley minimizes the effort required to lift an object. For example, when you pull down on a rope, the pulley allows you to lift an object upward without having to lift it straight up directly. This is particularly beneficial in situations where lifting straight up is impractical due to height or weight constraints.

The other options do not accurately describe the role of pulleys. While pulleys can make lifting easier, they do not inherently decrease the total work done; they merely change the direction of the applied force. Pulleys can lift weights at different angles and do not limit the lifting capability to just vertical movement. Additionally, pulleys do not increase the weight of objects; rather, they assist in lifting a given weight more effectively.