The force that stops or slows down motion is called friction.

Here's a breakdown:

* Friction is a force that opposes motion between two surfaces in contact.

* It arises from the microscopic irregularities on the surfaces that interlock and resist movement.

* Friction can be static (when objects are at rest) or kinetic (when objects are moving).

Here are some examples of friction in action:

* Walking: Friction between your shoes and the ground allows you to walk without slipping.

* Braking a car: Friction between the brake pads and the rotors slows the car down.

* Pushing a heavy box: Friction between the box and the floor makes it harder to move.

Let me know if you'd like to learn more about friction!