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23 Cards in this Set
- Front
- Back
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Newton's First Law of Motion
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A body continues in a state of rest of in a uniform motion of a straight line unless made to change by outside forces acting on it
(A body at rest stays at rest) (A body in motion stays in motion) |
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Newton's Second Law of Motion
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F=ma
Force = mass x acceleration The amount of acceleration that a force can produce depends directly on the mass of the object being accelerated |
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Newton's Third Law of Motion
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m1 x a1 = m2 x a2
When two bodies interact, they create equal and opposite forces on each other |
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Newton's Law of Gravity
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F = (G x m1 x m2) / R^2
Every mass exerts a force of attraction on every other mass *NOTE: R is the distance between the two masses |
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Kepler's Third Law of Orbital Motion
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P^2 = (4 x π^2 x a^3) / [G x (m1 + m2)]
Describes the orbits of two bodies around their center of mass, following directly from Newton's Law of Gravity *NOTE: P is the orbital period and a is the distance of the semi-major axis (the radius) |
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Light
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Also known as electromagnetic radiation, it is the fastest thing in the universe and doesn't need any medium to carry it (can travel in a vaccum)
Contains both a wave-like property (classic model of alternating electric and magnetic fields) and a particle-like property (quantum model made up of discrete packets of photons) |
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Speed of Light
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3 x 10^5 km/sec
Constant (never changes) and is the same for all observers regardless of relativity |
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Five Fundamental Properties of Light
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Speed (c)
Direction Wavelength (or frequency) Polarization Amplitude (or Intensity) |
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Wavelength Classification
(in decending wavelength) |
Gamma Rays
X-Rays Ultraviolet Visible Infrared Microwaves Radio Waves Only Visible and Radio waves can pass through the Earth's atmosphere (some infrared wavelengths as well) |
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Blackbody
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An idealized, opaque body at a uniform temperature which reflects no light but emits light with a specific spectral distribution given by Planck's Law
Gives a pure measurement of temperature because the radiation it does emit is entirely the result of its temperature |
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Wien's Law
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Max Wavelength = (0.0029 Km) / T
Describes the wavelength at which the intensity of a blackbody peaks |
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Flux
(and the Stephon-Boltzmann Law) |
F = σ x T^4
Reflects the total energy emitted per unit of time (second) per unit of area at the surface of a blackbody *NOTE: Strong temperature dependance |
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Luminosity
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L = 4 x π x σ x R^2 x T^4
Describes the total amount of energy a body is emitting per unit of time (second) |
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Spectral Dispersions:
1. Continuous Spectrum 2. Emission-Line Spectrum 3. Absorption-Line Spectrum |
1. Emitted by a perfect blackbody
2. Emitted when radiation passes through a gas cloud in front of a cold background (produces bright lines) 3. Emitted when radiation from a hot blackbody passes through a gas cloud that absorbs specific lines (produces spectrum with lines missing) |
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Importance of Spectral Lines
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Identification of atoms and molecules
Relative Abundances of different atoms and molecules Physical conditions (temperture, density, etc) Velocities |
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Four Fundamental Forces of Nature
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1. Gravity
2. Electromagnetism 3. Strong Nuclear Force 4. Weak Nuclea Force |
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Hydrostatic Equilibrium
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A balance of forces in stars that balances the force of inward gravity with outward pressure
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The Proton - Proton Chain
(Nuclear Fusion) |
1. Two Hydrogen fuse to produce deuterium, a positron, and a neutrino
2. A Hydrogen and a deuterium fuse to produce a Helium 3 and a gamma ray photon 3. Two Helium 3's fuse to produce a normal Helium and two Hydrogens NET RESULT: Four Hydrogen produce one Helium, two positrons, two neutrinos, and two gamma ray photons in the end |
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Efficiency of Nuclear Fusion and the Proton - Proton Chain
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0.7% efficiency
Efficiency = 0.03/4 Efficiency = energy output/total input |
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Lifetime of a Star
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time = Mass ^ -2.5
Lifetime of a star is almost entirely determined by its mass |
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Stellar Paralax
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d = 1/p
The apparent motion of nearby stars against a more distant background of stars, galaxies, or quasars caused by the orbital motion of the Earth around the sun *NOTE: D is in parasecs and p is in arcseconds |
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Brightness
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b = L / (4 x π x d^2)
Similar to flux in that it measures energy per time per area; however, brightness measures this quality some distance away from the object and not at the surface *NOTE: If brightness and luminosity are known, then it is possible to find distance |
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Standard Candles and the distance ladder
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1. Parallax Angles
2. Cepheid Variable stars 3. Type Ia Supernovea |
