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| tells both the speed and direction of an object |
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| how far an object will go in a certain amount of time |
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| when the velocity changeds in any way, whether in speed or direction or both |
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| the acceleration of a falling object |
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| the product of its mass and velocity; momentum=(mass)(velocity) |
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| the only way to change an object's momentum |
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| the only way to change an object's momentum |
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| overall force; represents the combined effect of all the individual forces put together |
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| "circling momentum" or "turning momentum"; any object that is either spinning or moving along a curved path as angular momentum |
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| the type of force that can change an object's angular momentum ("twisting force") |
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| the amount of matter in your body |
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| the force that a scale measures when you stand on it; that is, weight depends both on your mass and on the forces (including gravity) acting on your mass |
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| falling without any resistance to slow you down |
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| Newton's First Law of Motion |
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| An object moves at constant velocity if there is no net force acting upton it. "Objects will remain in moetion unless a force acts to stop them." |
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| Newton's Second Law of Motion |
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| The amount of the acceleration depends on the object's mass and the strength of the net force. force=(mass)(acceleration) |
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| Newton's Third Law of Motion |
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| For any force, there is always an equal and opposite reaction force. |
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| the total momentum of interacting objects cannot change as long as no external force is acting on them; that is, their total momentum is conserved. (Example, balls on a pool table) |
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| conservation of angular momentum |
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| as long as there is no external torque, the total angular momentum of a set of interacting objects cannot change. An individual object can change its angular momentum only by transferring some angular momentum to or from another object. (example, ice skater) |
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| mass (of the Earth) x velocity x radius (of the orbit) |
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| rotational angular momentum |
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| the same idea as orbital angular momentum explains why Earth keeps rotating. |
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| energy cannot appear out of nowhere or disappear into nothingness. objects can gain or lose energy only by exchanging energy with other objects. |
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| stored energy which might later be converted into kinetic or radiative energy (example, standing at the edge of a cliff) |
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| kinetic energy, represents the collective TOTAL kinetic energy of the many individual particles (atoms and molecules) moving randomly within a substance |
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| measures the AVERAGE kinetic energy of particles in a substance |
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| coldest temperature is absolute zero |
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| gravitational potential energy |
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| depends on an objects mass and how far it can fall as a result of gravity |
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| energy contained in mass; mass can be converted to other forms of energy with E=mc2 |
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| universal law of gravitation |
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1. Every mass attracts every other mass through the force called gravity.
2. The strength of the gravitational force attracting any two objects is directly proportional to the product of their masses.
3. The strength of gravity between 2 objects decreases with the square of the distance between their centers (INVERSE SQUARE LAW). |
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| elliptical; orbits in which an object goes around another object over and over again |
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| hyperbolic and parobolic, paths that bring an object close to another object just once |
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p2=a3
p-planet's orbital period in years
a-the planets avg distance from the Sun in AU |
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| Newton's version of Kepler's third law |
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| allows us to measure orbital period and distance in any units we wish (rather than only in years and AU); the relationship between the orbital period and the avg distance depends on the masses of the orbiting objects |
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| the sum of its kinetic and gravitational potential energies |
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| when two objects pass near enough so that they can feel the effects of the other's gravity (ex comet passes near a planet, the comet's orbit can change dramatically) |
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| minimum velocity required to escape Earth's gravity if a spacecraft starts near the surface |
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| the gravitational attraction of each part of Earth to the Moon becomes weaker as we go from the side of Earth facing the Moon to the side facing away from the Moon - stretches the entire Earth to create 2 tidal bulges |
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| like the Moon always showing the same face to the Earth |
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how we measure power
1 watt=1 joule |
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| distance from one peak to the next |
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| the number of peaks passing by any point each second |
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| how fast wave peaks are traveling |
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| electric and magnetic; describe the strength of the force that any particle would experience at any point in space |
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| 300,000 km per second; the longer the wavelength, the lower the frequency |
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| pieces of light that have properties of both particles and waves |
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| complete spectrum of light |
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| Light itself is often called... |
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| ...electromagnetic radiation. |
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| the longest wavelength of light |
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| between infrared and radio waves |
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| shorter wavelengths than blue light |
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| between ultraviolet and gamma |
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| the shortest-wavelength light |
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| make up elements; contain protons, neutrons, electrons, nucleus |
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| properties of an atom depend mainly on this; describes how strongly an object will interact with electromagnetic fields |
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| number of protons in the nucleus |
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| protons and neutrons in an atom |
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| versions of an element with different numbers of neutrons |
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| interactions between electrons that hold the atoms in a molecule together |
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| when molecules split into pieces |
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| the loss of one or more negatively charged electrons leaves the remaining atom with a net positive charge |
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| the process of stripping electrons from atoms |
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| hot gas, in which atoms have become ionized |
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| the force per unit area pushing on an object's surface |
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| only a few particular energies are possible, and energies between these special few are not possible. the possible energies are known as the energy levels of an atom |
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| an electron can rise from a low energy level to a higher one or fall from a high level to a lower one |
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| amount of radiation at different wavelengths |
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| consists of bright emission lines against a black background |
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| continuous light background with black absorption lines |
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| temperature dependence of light; blackbody radiation; thermal radiation spectra are the most common type of continuous spectra |
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| (Example: train or light moving closer or farther away) |
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| the Doppler shift of an object coming toward us |
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| the Doppler shift of an object moving away from us |
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| wavelengths in stationary clouds of hydrogen gas |
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| the place where the image appears in focus on the lens |
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| any device that records light |
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| charge-coupled devices; electronic devices; a chip of silicon that is extremely sensitive to photons |
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| picture elements - a grid of squares |
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| how much total light the telescope can collect at one time |
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| the smallest angle over which we can tell that two dots are distinct |
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| the angular resolution that a telescope could achieve if it were limited only by the interference of light waves |
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| operates like an eye, using trasparaent glass lenses to collect and focus light; earliest telescopes |
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| uses a precisely curved primary mirror to gather light. this mirror reflects the gathered light to a secondary mirror that lies in front of it. |
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| separating the various colors of light into spectra, which are then recorded with a detector |
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| graphs that show how an object's intensity varies with time |
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| winds and other air currents ensure that air in our atmosphere is constantly moving and mixing around |
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| technology that can eliminate much of the blurring in images caused by our atmosphere |
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| most common; every satellite dish is essentially a small radio telescope designed to collect radio waves from a satellite in Earth's orbit (like reflecting telescope) |
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| SOFIA (airborne observatory); most infrared can only be seen from mountain tops or in the air |
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| like infrared, must be done from the sky, because Earth's atmosphere absorbs almost all ultraviolet light |
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| grazing incidence mirrors |
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| x rays merely graze their surfaces as they are deflected toward the focal plane; xrays are difficult to focus on |
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| massive to withstand gamma-rays |
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| takes advantage of the wavelike properties of light that cause interference; the procedure relies on precisely timing when radio waves reach each dish and on using computers to analyze the resulting interference patterns |
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