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newton's laws
| Question | Answer |
|---|---|
| 1st law | law of inertia |
| inertia | tendency of an object NOT to accelerate |
| when the external force is zero... | it's acceleration i s zero |
| objects in motion or rest will stay in motion or at rest UNLESS... | acted on by an external force |
| mass | is a measure of inertia |
| inertia | is a measure of mass |
| inertia is NOT... | a measure of weight |
| weight... | is a measure of local gravity on mass |
| net external forces are... | vector sum of all forces acting on an object |
| the net external forces are...` | F(friction), F(gravity), F(normal), F(applied) |
| equilibrium... | condition in which net external forces equal zero |
| 2nd law | law of impulse |
| impulse is... | a force acting over a time |
| law of impulse is most often used for... | collisions and impacts |
| the acceleration of an object us directly proportional to... | the net force acting on the object and inversely proportional to the objects mass |
| F= | ma |
| 3rd law | law of interaction |
| interaction is... | when two or more objects act on one another |
| forces often exist in... | pairs |
| net external force | F(gravity)= weight, F(normal)=rxn to weight, F (application)=outside force, F(friction)= rxn to outside force |
| forces tend... | to work in pairs |
| forces of friction | dry, fluid, lubricated, skin, internal |
| dry friction | static and kinetic |
| static friction | resists against movement |
| kinetic friction | resists while moving |
| fluid friction | mostly related to chemicals |
| lubricated friction | mostly related to engines |
| skin friction | introduces drag and affects airplanes and swimmers |