How do astronomers test models of stellar evolution?
A. by measuring the number of stars in a cluster and comparing with the number predicted by the models
B. by assuming that all the stars in our galaxy formed at the same time, and comparing with predictions of the models
C. by recording the properties of a star over an extended period of time
D. by comparing the paths in the H-R diagram predicted by models with the H-R diagrams of star clusters
Answer: D
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The asteroid belt is located ________
A) between the orbits of Earth and Mars B) beyond the orbit of Neptune C) between the orbits of Jupiter and Saturn D) between the orbits of Mars and Jupiter
An electric clothes dryer draws 10 A at 220 V. If the clothes put into the dryer have a mass of 10 kg when wet and 3 kg dry, about how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water, Lv = 2.26 × 10^6 J/kg)
a. 171 min b. 120 min c. 51 min d. 40 min e. 5 min
As air rises, it expands. It expands because it moves to
A) a region of higher air pressure. B) a region of lower air pressure. C) an area of greater humidity. D) an area of cooler air temperature.
In Part A, you found that Planet Z should not have strong winds and violent storms. What single change to Planet Z's characteristics would cause it to have strong winds and violent storms?
a. a greater distance from its star b. a faster rotation rate c. a smaller size d. a larger axis tilt