| Term | Definition |
|---|---|
| Force | A push or a pull. |
| Contact force | A push or a pull on one object by another that is touching it. |
| Non-contact force | A force that one object can apply to another object without touching it. |
| Newton | The SI unit for force. |
| Gravity | An attractive force that exists between all objects that have mass. |
| Mass | The amount of matter in an object. |
| Kilogram | The SI unit for mass. |
| Weight | Gravitational force exerted on an object. |
| Friction | A force that resists the motion of two surfaces that are touching. |
| Net force | The combination of all the forces acting on an object. |
| Balanced force | Forces acting on an object that combine and form a net force of zero. |
| Unbalanced force | Forces acting on an object that combine and form a net force that is not zero. |
