Anti rust pulley of refrigerator
rust pulley of refrigerator definition
Movable pulley and lever
Definition 1: when using a pulley, the pulley whose position of the shaft moves with the pulled object is called a moving pulley.
Definition 2: if the weight is directly hung on the pulley, the pulley also rises when lifting the weight. Such a pulley calls the pulley.
principle
The movable pulley saves 1 / 2 of the force and twice the distance. This is because when using the movable pulley, the hook code is hung by two sections of rope, each section of rope only bears half of the weight of the hook code, and the direction of the force cannot be changed. In essence, it is a lever in which the power arm (L1) is twice the resistance arm (L2): in the figure, O is the fulcrum, F1 is the power to lift the object, F2 is the gravity of the object (which can also be understood as the force to lift the object without machinery), we have (L1 is the power arm, L2 is the resistance arm):
According to the principle that no machine can save work, we have (S1 is the moving distance of the free end of the rope, S2 is the moving distance of the object, which can also be understood as the lifting distance of the object without machinery).
be careful
The moving rust pulley of refrigerator pulley saves 1 / 2 of the force and costs twice the distance, and is limited to the vertical upward force. The greater the angle of force inclination, the more force is used. Moreover, when using the movable pulley, the weight of the pulley also affects the force used. When the gravity of the pulley is not ignored and the force is applied vertically, we have: F = (g wheel + G object) / 2.
