Term
If Earth were three astronomical units from the Sun, the force of gravity between the Earth and the Sun would be 1/9th as strong as it is now.
Why? |
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Definition
g (M1 X M2)/d^2
This problem refers to the d
If d= 3 in this instance, then the answer is 1/d^2 or 1/9 |
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Term
As an object cools from 2000 Kelvin to 1000 Kelvin, how does the total amount, and the color, of light coming from that object change?
-The total amount of light would decrease and the color would become redder.
Why |
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Definition
| The Stefan-Boltzmann Law, which states that each square meter of a hotter object’s surface emits more light at all wavelengths (if something is hotter it emits more light) |
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Term
If you are driving at 30 miles per hour and increase your speed to 60 miles per hour, your kinetic energy will increase by 4 times.
Wh |
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Definition
KE=1/2 (mv^2), but the mass of the object isn’t changing, only the velocity is, so m can be ignored and become “1”
½ (1)(30)^2=450
½ (1)(60)^2=1800
1800/450=4 |
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Term
A gamma ray photon has more energy and a shorter wavelength than a photon of visible light.
Why: |
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Definition
| According to the Electromagnetic Spectrum, gamma ray photons have shorter wavelengths and therefore more energy and a higher frequency than visible light |
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Term
The first law of planetary motion states that planets orbit their stars in ellipses.
Wh |
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Definition
| Kepler’s first law of planetary motion states that planets orbit their stars in ellipses, which tells us essentially that a planet’s distance from its star varies during its orbit |
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Term
The number of circumpolar constellations increases as you move north on the Earth.
Why |
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Definition
| Because as you move further North, you become closer to Polaris, the star around whom all circumpolar constellations rotate around |
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Term
| When making observations with the naked eye, we may express an object’s location in the sky using the local coordinate system of altitude and azimuth. Why |
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Definition
| Azimuth is the degrees clockwise from due north, (the direction), and altitude is distance from the horizon |
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Term
The gravitational force of Jupiter on Io is the same as the gravitation force of Io on Jupiter.
Why |
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Definition
| according to the gravitational force law, the force between 2 objects is the same --> GM1(M2)/R^2 |
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Term
4. The advent of astrophysics resulted from the fusion of astronomical theory and observations exemplified by Tycho and Kepler whose join efforts resulted in the three laws of planetary motion.
Why |
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Definition
| Tycho never was able to explain planetary motion. Kepler’s key discovery was that planetary orbits are not circles but instead are special ovals called ellipses. First law: the orbit of each planet around the Sun is an ellipse with the Sun at one focus. Second law: as a planet moves around its orbit, it sweeps out equal areas at equal times --> planets travel faster when they are nearer to the Sun. Third law: more distant planets orbit the sun at slower speeds --> p^2 = a^3 (p in years and a in AU) |
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Term
Conservation of angular momentum says that a spinning object should speed up as it contracts.
Why |
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Definition
| with the ice skater --> by decreasing her radius (contracting), her velocity of rotation must increase. Stars and galaxies are both born from clouds of gas that start out much larger in size. These clouds almost inevitably have some small net rotation, so like the spinning skater as she pulls in her arms, they must therefore spin faster as gravity makes them shrink in size. |
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Term
| The position of the North Star in the sky can tell you your latitude on Earth –Why |
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Definition
| Its degree above the horizon can tell you your latitude, because it is at the rotational axis. The further North you go, the higher in the sky the North star goes. |
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Term
| An invisible object is one which does not emit light -Why |
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Definition
| It does not emit, absorb, reflect, or transmit light (like color) |
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Term
| A more massive object experiences a greater force towards the ground due to gravity than does a less massive object – Why |
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Definition
| Gravitational force is proportional to the product of the masses of Earth and the Object in question |
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Term
| The lower energy contained in a red light photon implies that it should be travelling slower than a blue light photon – Why |
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Definition
| The speed of light is constant. Low vs. high energy impacts wavelength size. |
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Term
| A waning gibbous Moon rises at approximately 9 pm. At midnight, approximately how many degrees above the horizon will the Moon be? |
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Definition
| 45 degrees in the sky, because the waning gibbous is its highest at 3 am so by midnight it should only be halfway to its highest point, (its highest point being 90 degrees, or straight up in the sky) |
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Term
| In what phase do we see the Moon when it is rising at noon? |
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Definition
| The first quarter moon, which rises from the East and reaches its highest point at 6 pm |
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Term
| At what time should you return a week later to observe the Moon rising? |
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Definition
| I would return at 6 pm, because every day the rising time of the Moon changes by 1 hour. |
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