Download Terms and Definitions in Physics: From Ancient Models to Modern Laws and more Quizzes Astronomy in PDF only on Docsity! TERM 1 models DEFINITION 1 a representation of some aspect of nature that can be used to explain and predict real phenomena without invoking myth, magic, or the supernatural TERM 2 Ptolemaic model DEFINITION 2 the geocentric model of the universe developed by Ptolemy in about 150AD TERM 3 Copernican revolution DEFINITION 3 the dramatic change, initiated by Copernicus, that occurred when we learned that Earth is a planet orbiting the Sun rather than the center of the universe TERM 4 ellipse DEFINITION 4 a type of oval that happens to be the shape of bound orbits TERM 5 foci/focus DEFINITION 5 one of two special points within an ellipse that lie along the major axis TERM 6 semimajor axis DEFINITION 6 half the distance across the long axis of an ellipse TERM 7 eccentricity DEFINITION 7 a measure of how much an ellipse deviates from a perfect circle; defined as the center-to-focus distance divided by the length of the semimajor axis TERM 8 Kepler's laws of planetary motion DEFINITION 8 three laws discovered by Kepler that describe the motion of the planets around the Sun TERM 9 perihelion DEFINITION 9 the point at which an object orbiting the Sun is closest to the Sun TERM 10 aphelion DEFINITION 10 the point at which an object orbiting the sun is farthest from the Sun TERM 21 netforce DEFINITION 21 the overall force to which an object responds TERM 22 angular momentum DEFINITION 22 momentum attributable to rotation of revolution TERM 23 mass DEFINITION 23 a measure of the amount of matter in an object TERM 24 weight DEFINITION 24 the net force that an object applies to its surroundings TERM 25 free-fall DEFINITION 25 the condition in which an object is falling without resistance TERM 26 weightless DEFINITION 26 a weight of zero, as occurs during free-fall TERM 27 Newton's laws of motion DEFINITION 27 three basic laws that describe how objects responds to forces TERM 28 conservation of momentum DEFINITION 28 the principle that, in absence of net force, the total momentum of a system remains constant TERM 29 conservation of angular momentum DEFINITION 29 the principle that, in the absence of net torque, the total angular momentum of a system remains constant TERM 30 kinetic energy DEFINITION 30 energy of motion TERM 31 radiative energy DEFINITION 31 energy carried by light TERM 32 potential energy DEFINITION 32 energy stored for later conversion into kinetic inergy TERM 33 joule DEFINITION 33 the international unit of energy, equivalent to about 1/4000 of a Calorie TERM 34 thermal energy DEFINITION 34 the collective kinetic energy, as measured by temperature, of the many individual particles moving within a substance TERM 35 Kelvin DEFINITION 35 the most commonly used temperature scale in science
