Here's why:

* Contact forces require physical contact between objects for them to act.

* Non-contact forces can act over a distance, like gravity or magnetism.

Some examples of contact forces include:

* Normal force: The force that a surface exerts on an object resting on it.

* Friction: The force that opposes motion between two surfaces in contact.

* Tension: The force exerted by a string, rope, or cable when pulled.

* Applied force: The force applied directly to an object, like pushing or pulling.

Let me know if you have any other questions!