Who can summarize the junior high school physics inside about the pulley block, the lever aspect knowledge? Better be more detailed

Who can summarize the junior high school physics inside about the pulley block, the lever aspect knowledge? Better be more detailed

Under the action of force, if a hard rod can rotate around a fixed point, it is called a lever. In life, according to needs, the lever can be made straight or curved. The fixed pulley is an equal arm lever, the movable pulley is a kind of lever, and the power arm is twice of the resistance arm. The condition of lever balance: power x power arm = resistance x resistance arm or