Contact forces are the pushes or pulls that occur when two objects touch each other. These forces can be classified into several types, including friction, tension, normal force, and applied force. Each type of contact force plays a crucial role in how objects interact in our daily lives, such as when we push a door open or slide a book across a table. When two surfaces come into contact, they exert forces on each other. For example, friction opposes the motion of an object, while normal force acts perpendicular to the surfaces in contact, supporting the weight of an object. Understanding contact forces helps explain how objects move and interact in the physical world.