| A | B |
|---|
| air resistance | the fluid friction experienced by objects falling throught the air |
| balanced forces | equal forces acting on an object in opposite directions |
| compression | an elastic force that squeezes or pushes matter together |
| first law of motion | law that states an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by an unbalanced force |
| fluid friction | friction that occurs when a solid object moves through a fluid (liquid or gas) |
| force | a push or a pull exerted on an object |
| free fall | the motion of a falling object when the only force acting on it is gravity |
| friction | the force that one surface exerts on another when the two surfaces rub against each other |
| gravity | the force that pulls objects toward each other |
| inertia | the tendency of an object to resist any change in motion |
| law of conservation of momentum | the rule that in the absence of outside forces the total momentum of objects that interact does not change |
| law of universal gravitation | the scientific law that states that every object in the universe attracts every other object |
| mass | a measure of how much matter is in an object |
| momentum | the product of an object's mass and velocity |
| net force | the overall force on an object when all the individual forces acting on it are added together |
| newton | a unit of measure that equals the force required to accelerate 1 kg of mass at 1m/s/s |
| projectile | an object that is thrown |
| rolling friction | friction that occurs when an object rolls over a surface |
| second law of motion | law that states that acceleration depends on the net force acting on an object and on the object's mass |
| sliding friction | friction that occurs when one solid surface slides over another |
| static friction | friction that acts on objects that are not moving |
| tension | elastic force that stretches or pulls matter |
| third law of motion | law that states that if one object exerts a force on another objects, then the second object exerts a force of equal magnitude(strength) and in the opposite direction on the first object. |
| unbalanced forces | forces that produce a nonzero net force, which changes an object's motion |
| weight | a measure of the force of gravity on an object |
