What is the mechanical advantage of single fixed pulley?

Hint: A pulley is a mechanical device used to lift objects. It is made in such a way that the applied force has direction opposite of the direction of motion. The pulleys can be used as a lift in a variety of places like in wells to lift water, etc.

Complete step by step answer:
A pulley is a very simple machine which consists of a wheel around which a rope or chain is wound. One of the ends of the rope is attached to a load which can be lifted by pulling the rope from the other side.
The main use of pulleys is to lift heavier loads. They can be three types of pulleys in use.
1) One which has a fixed axle
2) One which has a moving axle
3) One which has a combination of both of these and is called compound pulley.
In a single fixed pulley as shown in the figure, we have a pulley fixed to the ceiling and the wheel can rotate about the axle. We need to apply force equal to the load of the weight that is to be lifted which is considered as the mechanical advantage of a single fixed pulley. The force applied is in the direction opposite to the direction of motion of the load.

Note: A pulley is a simple machine which might be in use from Archimedes’ time. It is basically used to change the direction of force. Picking something vertically upwards requires more force than when lifted by changing direction as in the case of a pulley.