The image shows three physics diagrams. Describe the physical principles illustrated in each diagram.

The image displays three distinct physics diagrams, each illustrating fundamental principles of mechanics:

• Top Diagram: This diagram depicts the concept of vector addition, likely representing forces. Two vectors, F₁ and F₂, are shown originating from a point C. Their resultant vector, F, is then graphically determined using the parallelogram rule (or triangle rule, if one vector was placed head-to-tail with the other). This illustrates how multiple forces acting on an object can be combined into a single equivalent force.
• Middle Diagram: This diagram illustrates the principle of equilibrium and the use of a spring scale. A lever is balanced on a fulcrum. A spring scale measures a downward force F, while weights labeled P are hung on the other side, indicating a force that is being counteracted. The setup likely demonstrates how to measure forces and determine conditions for equilibrium on a lever.
• Bottom Diagram: This diagram illustrates the principle of a lever, specifically a first-class lever. A person applies an upward force F₁ at point A to lift a heavy object (represented by a box) at point B, which exerts a downward force F₂. The diagram shows the fulcrum at A, the effort at A, the load at B, and the resistance at C. This setup is used to demonstrate mechanical advantage, where a smaller input force can overcome a larger output force by utilizing the lever's geometry.