The Cosmic Perspective: Making Sense of the Universe (Chapter 4) Flashcards
The condition in which an object is falling without resistance
Free-fall
In the absence of a net force, an object moves with constant velocity
Newton’s First Law of Motion
Law states how a net force affects an object’s motion; force = mass X acceleration
Newton’s Second Law of Motion
For any force, there’s always an equal and opposite reaction of the force
Newton’s Third Law of Motion
The international unit of energy, equivalent to about 1/4000 of a Calorie
Joule
An encounter in which two (or more) objects pass near enough so that each can feel the effects of the other’s gravity and can therefore exchange energy
Gravitational Encounter
The most commonly used temperature scale in science is defined such that absolute zero is OK and water freezes at 273.15K
Kelvin
The temperature scale commonly used in daily activity internationally defined so that, on Earth’s surface, water freezes at 0 degrees Celsius and boils at 100 degrees Celsius
Celsius
The law expresses the force of gravity between two objects
Universal Law of Gravitation
Momentum attributable to rotation or revolution
Angular Momentum
The speed necessary for an object to escape the gravity of a large body (moon, planet, or star)
Escape Velocity
A law followed by any quantity that decreases with the square of the distance between two objects
Inverse Square Law
Orbits on which an object travels repeatedly around another object
Bound Orbits
The portion of any object’s total velocity that’s directed across our line of sight as it can only be measured by observing the object’s gradual motion across our sky
Tangential Velocity
The potential energy that can be released through chemical reactions
Chemical Potential Energy
The higher-than-average tides on Earth that occur at new and full moon, when the tidal forces from the Sun and Moon both act along the same line
Spring Tides
The amount of mass per unit volume of an object; it’s more commonly stated in units of grams/cubic centimeter in Astronomy
Density (Mass)
The sum of an orbiting object’s kinetic and gravitational potential energies
Orbital Energy
A measure of the average kinetic energy of particles in a substance
Temperature
The three basic laws that describe how objects respond to forces
Newton’s Laws of Motion
The standard unit of force in the metric system
Newton
The lower-than-average tides on Earth that occur at first- and third-quarter moon, when the tidal forces from the Sun and Moon oppose each other
Neap Tides
Energy carried by light
Radiative Energy
A generalization of Kepler’s third law used to calculate the masses of orbiting objects from measurements of orbital period and distance
Newton’s version of Kepler’s third law
The precise mathematical shape of one type of unbound orbit (The other is a parabola) allowed under the force of gravity
Hyperbola
The coldest possible temperature, which is 0K
Absolute Zero
The proposed force that exists at very high energies when the strong, weak, and electromagnetic forces all act as one
GUT Force
Friction within an object that’s caused by a tidal force
Tidal Friction
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
Tidal Force
The rate at which an object’s velocity changes; standard units are Mass/Speed^2
Acceleration
Energy stored for later conversion into kinetic energy; includes gravitational, electrical, and chemical potential energies
Potential Energy
The experimentally measured constant G that appears in the law of universal gravitation
Gravitational Constant
The collective kinetic energy, as measured by temperature, of the many individual particles moving within a substance
Thermal Energy
A weight of zero, as occurs during free-fall
Weightlessness
A satellite that orbits Earth in the same time it takes Earth to rotate (one sidereal day)
Geosynchronous Satellite
