How do Forces Arise
To make anything move it requires a force. Forces are usually represented by an arrow on a diagram as they cannot be seen.
Forces always arise from an interaction between two objects. Forces always come in pairs and the two forces in an interaction pair are equal in size and opposite in direction and these forces always act on the opposite objects.
When the interacting objects touch each other it is called a contact force. There are also forces which act at a distance, examples of these forces are gravity and magnetism.