Question | Answer |
Reference point | A point against which position is measured |
Vector quantity | A physical measurement that contains directional information |
Scalar quantity | A physical measurement that does NOT contain directional information |
Acceleration | the time rate of change of an object's velocity |
Free fall | the state of an object that is falling towards the earth with nothing inhibiting its fall |
Friction | A force resulting from the contact of two surfaces. This force opposes motion |
Static friction | The friction that exists between surfaces when neither surface is moving relative to the other. |
Kinetic friction | The friction that exists between surfaces when at least one of those surfaces is moving relative to the other. |
Newton's 1st Law | The velocity of an object will not change unless the object is acted on by an outside force. |
Newton's 2nd Law | When an object is acted on by an outside force, the strength of that force is equal to the mass of the object times the resulting acceleration. |
Newton's 3rd Law | For every action, there is an equal and opposite reaction. |
4 Fundamental Forces | gravitational, weak, strong, electromagnetic |
photons | small "packages" of light that act just like small particles |
charging by conduction | charging an object by allowing it to come into contactwith an object which already has an electrical charge |
charging by induction | charging an object by forcing some of the charges to leave the object |
electrical current | the amount of charge that travels through an electrical circuit each second |
conventional current | current that flows from the positive side of the battery to the negative side. This is the way current is drawn in circuit diagrams, even though it is wrong |
resistance | a measure of how much a metal impedes the flow of electrons |
open circuit | a circuit that does not have a complete connection betweenthe two sides of the battery. As a result current does not flow. |
transverse wave | a wave whose direction is perpendicular to its up and down motion |
longitudal wave | a wave whose direction is parallel to its up and down motion |
supersonic speed | any speed that is faster than the speed of sound in the substance of interest |
sonic boom | the sound produced as a result of aircraft traveling at or above Mach 1 |
pitch | the highness or lowness of a sound |
nuclear fusion | the process by which two or more nuclei fuse to make a bigger nucleus |
nuclear fission | the process by which a large nucleus is split into two smaller nuclei |
critical mass | the amount of isotope necessary to cause a chain reaction |
star magnitude | the brightness of a star on a scale of -8 to +17. Smaller the number the brighter the star. |
Light year | the distance light travels in one year. |
galaxy | a massive ensemble of hundreds of millions of stars, all interacting through the gravitational force, orbiting around a common center |