| A | B |
|---|
| force | a push or a pull exerted on an object |
| newton | SI unit of force; amount of force needed to accelerate 1 kg at 1m/s/s |
| net force | overall force on an object; found by adding together all forces acting on it |
| unbalanced forces | forces that change an object's motion |
| balanced forces | equal but opposite forces acting on an object; produce no change in motion |
| friction | forces that are exerted when one surface rubs on another |
| static friction | friction acting on objects that are not moving |
| sliding friction | occurs when 2 solid surfaces slide over each other |
| rolling friction | occurs when an object rolls over a surface |
| fluid friction | occurs when a solid object moves through a liquid or a gas |
| gravity | force that pulls objects towards each other |
| mass | the amount of matter in an object |
| weight | the force of object pulling on an object |
| free fall | occurs when the only force acting on a falling object is gravity |
| air resistance | fluid friction acting on objects falling through the air |
| terminal velocity | the greatest velocity a falling object can achieve |
| projectile | an object that is thrown |
| inertia | resistance to change in motion |
| momentum | mass times velocity |
| law of conservation of momentum | in the absence of outside forces, the total momentum of objects that interact does not change |
| satellite | any object that orbits another in space |
| centripetal force | a force that causes an object to move in a circular path |
