Here's why:

* Contact forces require physical contact between two objects. This contact allows for the transfer of force.

* Examples of contact forces:

* Normal force: The force that a surface exerts on an object in contact with it (like a table supporting a book).

* Frictional force: The force that opposes motion between two surfaces in contact (like the force that slows down a sliding box).

* Tension force: The force transmitted through a string, cable, or rope when it's pulled taut (like pulling a toy on a string).

* Applied force: The force that is directly applied to an object by a person or another object (like pushing a door).

Non-contact forces act on objects without any physical contact. They include:

* Gravitational force: The force of attraction between any two objects with mass.

* Electromagnetic force: The force that arises from the interaction of charged particles. This includes forces like magnetism and electricity.

Let me know if you have any more questions!