* Increased Contact Area: Pressing harder increases the area of contact between the surfaces. This means more points of contact are interacting, leading to a greater force of friction.
* Increased Normal Force: The force pressing the surfaces together is called the normal force. This force is directly proportional to the frictional force. A higher normal force results in a greater frictional force.
In simpler terms: Think of it like pushing a heavy box across the floor. If you push harder (increase the normal force), it becomes more difficult to move (increased frictional force).
Important Note: This relationship holds true for both static friction (friction that prevents motion) and kinetic friction (friction that opposes motion).
