A pulley is a wheel or a circular disc that can rotate freely about its axle. It is used to lift heavy objects. It is neither a force multiplier nor a speed multiplier. It only changes the direction of the applied force from upwards against gravity to downwards towards gravity.
There are two types of pulley systems – Single fixed pulley and single movable pulley.
| Single fixed pulley | single movable pulley |
| i. This pulley has fixed axis of rotation. | The axis of rotation of this pulley is not fixed. |
| ii. The load is attached to one end of the pope | The load is attached to the pulley. |
| iii. only the direction of the force is changed, not the magnitude, [we can lift the object higher bur heaviness of load ******* the same] | The direction of the force as well as the magnitude of force change. |
| iv. The mechanical advantage of this pulley is 1. | The mechanical advantage of this pulley is 2 |
| v. Example : used to draw water from wells, | Example: used in construction cranes, weight lifting machine in gym etc, |
