Wendy measures a recession velocity for two distant galaxies, well outside our Local Group of galaxies. Galaxy A has a recession velocity of 35,000 km/s and Galaxy B has a recession velocity of 70,000 km/s
What can she say about the distances to those galaxies?
A) She can't say anything about the distances to Galaxy A or B.
B) Galaxy A is twice as far as Galaxy B.
C) Galaxy B is four times as far as Galaxy A.
D) Galaxy B is twice as far as Galaxy A.
E) Galaxy A is four times as far as Galaxy B.
D
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Thermal Expansion: Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is increased, the hole will
A. expand only if it takes up more than half the plate's surface area. B. contract if it takes up less than half the plate's surface area. C. always contract as the plate expands into it. D. always expand with the plate. E. remain the same size as the plate expands around it.
You are standing on a bathroom scale in an elevator that is moving upward at constant speed, when suddenly the cable breaks. From just before to just after the cable breaks, the reading on the scale
A. increases by a little bit B. decreases by a little bit C. remains the same D. decreases to zero
Why are dark dust clouds largely misnamed?
A) It is ice, not dust, which make them look dark. B) Dust clouds do radiate energy, but not as much light as the stars do. C) The cloud is an illusion, for the dust is evenly distributed around the Galaxy. D) They contain much more gas than dust. E) All of the above are correct.
The rate of cratering in the lunar highlands shows us that:
A) they must be younger than the older, darker mare. B) they range from 4.6-4.4 billion years old, on average. C) the largest impacts are the youngest, such as Copernicus and Tycho. D) the oldest rocks are at least as old as the mare, but some craters are much younger. E) most of the asteroids must have hit the Moon, not the Earth.