Chapter 4 Flashcards
Law of conservation of angular momentum
the principle that, in the absence of net torque, the total angular momentum of a system remains constant
Unbound orbits
orbits on which an object comes in toward a large body only once, never to return
Gravitational constant
the experimentally measured constant G that appears in the law of universal graviation
Radiative energy
energy carried by light
Kelvin
the temperature scale most commonly used in science
Kinetic energy
energy of motion
Tidal force
a force that occurs when the gravity pulling on one side of an object is larger than that on the other side, causing the object to stretch
Momentum
the product of an object’s mass and velocity
Net force
the overall force to which an object responds
Free-fall
the condition in which an object is falling without resistance
Thermal energy
the collective kinetic energy, as measured by temperature, of the many individual particles moving within a substance
Temperature
a measure of the average kinetic energy of particles in a substance
Escape velocity
the speed necessary for an object to completely escape the gravity of a large body such as a moon, planet, or star
Acceleration
the rate at which an object’s velocity changes
Bound orbits
Orbits on which an object travels repeatedly around another object
Angular momentum
momentum attributable to rotation or revolution
Speed
the rate at which an object moves
Mass
a measure of the amount of matter in an object
Acceleration of gravity
the acceleration of a falling object
Orbital energy
the sum of an orbiting object’s kinetic and gravitational potential energies
Newton’s version of Kepler’s third law
a generalization of Kepler’s third law used to calculate the masses of orbiting objects from measurements of orbital period and distance
Mass-energy
the potential energy of mass, which has an amount E=mc^2
Gravitational encounter
an encounter in which two objects pass near enough so that each can feel the effects of the other’s gravity and they can therefore exchange energy
Weight
the net force that an object applies to its surroundings
Universal law of gravitation
the law expressing the force of gravity (Fg) between two objects
Inverse square law
a law followed by any quantity that decreases with the square of the distance between two objects
Joule
the international unit of energy, equivalent to about 1/4000 of a Calorie
Velocity
the combination of speed and direction of motion
Gravitational potential energy
energy that an object has by virtue of its position in a gravitational field
Weightless
a weight of zero
Newton’s laws of motion
three basic laws that describe how objects respond to forces
Potential energy
energy stored for later conversion into kinetic energy
Force
anything that can cause a change in momentum
Law of conservation of energy
the principle that energy can be neither created nor destroyed, but can only change from one form to another
