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Physics ch. 16-17
Motion and force
Term | Definition |
---|---|
motion | distance from another object is changing |
reference point | a place or object used for comparison |
SI | international system of units (metric system) |
speed | the distance an object travels in a certain amount of time |
speed formula | S=D/T |
velocity | speed and direction of an object |
acceleration | the process of increasing speed, decreasing speed or changing direction |
acceleration formula | A=final speed-initial speed/ time |
force | a push or a pull |
newton | the SI unit of measurement for force |
unbalanced force | causes an object to move |
balanced force | an object will not move because there is equal pressure applied in both directions |
friction | the force applied when two surfaces rub against each other |
static friction | friction that acts on an object that is not moving |
sliding friction | friction that occurs when two solid surfaces slide over each other |
rolling friction | friction that occurs when an object rolls across a surface |
fluid friction | friction that occurs when a solid object moves through a fluid |
gravity | a force that pulls objects towards each other |
mass | the measure of the amount of matter in an object |
weight | the measure of the gravitational force exerted on an object |
free fall | when the only force acting on an object is gravity |
air resistance | objects falling through air experience this type of fluid friction |
terminal velocity | the fastest something can fall |
Inertia | the tendency of an object to resist a change in motion |
Newtons first law | an object at rest will stay at rest and an object in motion will stay in motion unless acted upon by an outside force |
Newtons second law | force equals mass times acceleration |
Newtons third law | for every action there is an equal and opposite reaction |
momentum formula | momentum=mass x velocity |
Law of conservation of momentum | the total momentum does not change in a collision unless acted upon by an outside force. |