Astronomy midterm 2

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Which of the following is an example in which you are traveling at constant speed but not at
constant velocity?
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Terms in this set (82)
Which of the following is an example in which you are traveling at constant speed but not at
constant velocity?
driving around in a circle at exactly 100 km/hr
What is the acceleration of gravity of Earth?
9.8 m/s2 downward
Momentum is defined as
mass times velocity
If an object's velocity is doubled, its momentum is
doubled.
You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?
The elevator is accelerating downwards.
What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?
It would travel away from Earth into the solar system.
Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will
continue to move in the same way until it is acted upon by a force.
Newton's second law of motion tells us that the net force applied to an object equals its
Mass times acceleration
The fact that the Voyager spacecraft continue to speed out of the solar system, even though its rockets have no fuel, is an example of
Newton's First Law of Motion
What quantities does angular momentum depend upon?
mass, velocity, and radius
A skater can spin faster by pulling her arms closer to her body or spin slower by spreading her arms out from her body. This is due toconservation of angular momentum.Absolute zero is0 KelvinWhat does temperature measure?the average kinetic energy of particles in a substanceSuppose you heat up an oven and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?The water has a higher heat content than the oven.The amount of gravitational potential energy released as an object falls depends onIts mass and the distance it fallsWhich of the following best describes the origin of ocean tides on Earth?Tides are caused by the difference in the force of gravity exerted by the Moon across the sphere of the earth.Which of the following scenarios correctly demonstrates the transformation of mass into energy as given by Einstein's equation, E = mc2?When hydrogen is fused into helium, whether in the Sun or in a nuclear bomb, the mass difference is turned into energy.Imagine we've discovered a planet orbiting another star at 1 AU every 6 months. The planet has a moon that orbits the planet at the same distance as our Moon, but it takes 2 months. What can we infer about this planet?It is less massive than EarthIn the formula E = mc2, what does E represent?the mass-energy, or potential energy stored in an object's massAt which lunar phase(s) are tides most pronounced (e.g., the highest high tides)?Both new and full moonsThe mass of Jupiter can be calculated bymeasuring the orbital period and distance of one of Jupiter's moons.According to what we now know from Newton's laws, which of the following best explains why Kepler's second law is true?A planet's angular momentum must be conserved as it moves around its orbit.The allowed shapes for orbits under the force of gravity areellipses, parabolas, and hyperbolasAccording to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them willdecreased by a factor of 9Which of the following is not a conserved quantity?RadiationIf a material is highly opaque, then itabsorbs most lightWhen light reflects off an object like a mirror, what is the relation between the angle of incidence and the angle of reflection?angle of incidence = angle of reflectionIf a material is transparent, then ittransmits light wellGrass (that is healthy) looks green becauseit reflects green light and absorbs other colorsThe frequency of a wave isall of the aboveHow are wavelength, frequency, and energy related for photons of light?Longer wavelength means lower frequency and lower energy.Suppose you built a scale-model atom in which the nucleus was the size of a tennis ball. About how far would the cloud of electrons extend?Several kilometersWhich of the following statements about electrical charge is true?A positive charge and a negative charge will attract each other.How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have?a positive charge of +1If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas producesan emission line spectrumWhich of the following objects is not a close approximation of a thermal emitter?hot, thin gasWhen white light passes through a cool cloud of gas, we seean absorption line spectrumIf one object has a large redshift and another object has a small redshift, what can we conclude about these two objects?The one with the large redshift is moving away from us faster than the one with the small redshift.The spectra of most galaxies show redshifts. This means that their spectral lineshave wavelengths that are longer than normal.A gas heated to millions of degrees would emitmostly X rays.Which of the following statements about thermal radiation is always true?A hot object emits more total radiation per unit surface area than a cool object.An electron-volt isan amount of energy much smaller than a joule.How can an electron in an atom lose energy to go from a higher energy level to a lower energy level?It releases a photon equal in energy to its own energy drop.Without telescopes or other aid, we can look up and see the Moon in the night sky because itReflects visible lightThe loss of an electron from a neutral helium atom results inionized heliumWhen an atom absorbs a photon containing energy, any of the following can happen except which?An electron moves from an upper energy level to a lower one.Sublimation is the process in whichmolecules go from the solid phase to the gas phase.At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter?a plasma consisting of positively charged ions and free electronsAn atom of the element iron has an atomic number of 26 and an atomic weight of 56. If it is neutral, how many protons, neutrons, and electrons does it have?26 protons, 30 neutrons, 26 electronsFrom shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation?gamma rays, X rays, ultraviolet, visible light, infrared, radioWhich of the following statements about light focusing is not true?The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes?The two stars will look like a single point of light.Which of the following is a principal advantage of CCDs over photographic film?CCDs capture a much higher percentage of the incoming photons than does film.Which of the following statements best describes the two principal advantages of telescopes over eyes?Telescopes can collect far more light with far better angular resolution.What do we mean by the diffraction limit of a telescope?It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.Currently, the largest optical telescope mirrors have a diameter of10 mWhich of the following could not be determined by an observation that uses only spectroscopy?the size of a distant galaxyWhat is meant by spectral resolution?It is a measure of how close two spectral lines can be distinguished.The largest effective telescope, created by radio interferometry, is the size ofEarthWhat does the technique of interferometry allow?It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes.In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate?radioWhich of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?It is closer to the starsWhy do astronomers need different telescope designs to observe across the electromagnetic spectrum?Photons of different energy behave differently and require different collection strategies.Which of the following is not a good reason to place observatories on remote mountain tops?to be able to observe at radio wavelengthsWhat is an artificial star?a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuationsWhat do astronomers mean by light pollution?Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.Which of the following is always true about images captured with X-ray telescopes?they are always displayed in false colorHow does the Sun's mass compare with that of the planets?It is a thousand times more massive than all the planets combined.Which planet has the highest average surface temperature, and why?Venus, because of its dense carbon dioxide atmosphereWhich planet, other than Earth, has visible water ice on it?MarsWhich of the following is farthest from the Sun?a comet in the Oort cloudWhich planet has a ring system?all of the aboveWhat is aerobraking?the technique of using a planetary atmosphere to change the orbit of a spacecraftWhich of the following statements is not an observed pattern of motion in our solar system?Most planets orbit at the same speed.Which of the following is not a pattern of motion in our solar system?Planets all rotate in the same direction.Which of the following is not an exception to the general patterns in the solar system?the rings of SaturnWhich of the following is not a characteristic of the inner planets?They all have substantial atmospheresWhich of the following is not a characteristic of the outer planets?They have very few, if any, satellites.How do asteroids differ from comets?Asteroids are rocky bodies and are denser than the comets, which are made of icy material.Where are most of the known asteroids found?between the orbits of Mars and JupiterThe planet closest in size to Earth isVenusWhich is the densest planet in the solar system?Earth