The Principle of Flag-Raising and Lowering Platforms Presentation

   In the current junior high school physics textbook for the teaching of pulleysUsing the principle of equivalent leverage of pulleys to demonstrate experimental facts is a great teaching material, which deepens the students' understanding and connection with the knowledge. In order to achieve a close synchronization of teaching and learning, we have developed a lever principle demonstration device for pulleys in our teaching, and now I would like to introduce it to you. 1. Design Concept: On actual pulleys, the demonstration device visually shows the equivalent lever principle, allowing students to better understand the concept.

Experimental Purpose: Because the pulley and the lever are equivalent in their effect.The working principle is the same, with supports, forces, resistances, lever arms, and resistance arms, and both pulleys and levers are simple machines that follow the principle of work. However, the supports of pulleys can be on the axis, on the wheel, or even moving, and their shapes can be different. But in terms of their effect, they are equivalent, so we can say that pulleys are also levers.

1. Experiment preparation: familiarize yourself with the experiment equipment: fixed pulley, base, pole, rope, flag.

Experiment Report:

The center axis of a fixed pulley remains stationary. The function of a fixed pulley is to change the direction of the force, but it cannot reduce the effort. When pulling a heavy object,
When using a fixed pulley, the direction of the applied force can be changed to make it easier to apply force. When using a fixed pulley, the distance pulled by the force is equal to the distance the object rises, and it cannot save effort nor does it consume effort. The tension in the rope is equal on both ends, so the output force is equal to the input force. Without considering friction, the mechanical efficiency of the fixed pulley is close to 1。