Forces bind things together and push things apart.
- The push-pull interactions between things are described as the interplay of forces.
- Forces explain how anything interacts with anything else in the whole of the natural world.
- Forces produce motion and can cause an object with mass to change velocity.
- Changes in velocity include causing things to start moving from a state of rest, to accelerate or slow down.
- Quarks and leptons, fundamental particles present in all forms of matter, are bound together by fundamental forces.
- There are four fundamental forces that account for all the forms of pulling and pushing between things in the Universe.