You discover a binary star system in which one member is a 15 solar mass main-sequence star and the other star is a 10 solar mass giant star. Why should you be surprised, at least at first?
A) The two stars should be the same age, so the more massive one should have become a giant first.
B) The two stars in a binary system should both be at the same point in stellar evolution; that is, they should either both be main-sequence stars or both be giants.
C) It doesn't make sense to find a giant in a binary star system.
D) A star with a mass of 15 solar masses is too big to be a main-sequence star.
E) The odds of ever finding two such massive stars in the same binary system are so small as to make it inconceivable.
A
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Indicate whether the statement is true or false
Two objects are at rest on a frictionless surface. Object 1 has a mass that is twice that of Object 2. When a constant force is applied to Object 1, it accelerates for a time interval ?t. The force is removed from Object 1 and is then applied to Object 2. After Object 2 has been accelerated for the same time interval, which statements are true?
(i) p2 = 2p1 (ii) p2 = p1 (iii) p2 = ½ p1 (iv) KE2 = 2KE1 (v) KE2 = KE1 (vi) KE2 = ½ KE1
1.(i) and (vi) 2.(ii) and (iv) 3.(i) and (v) 4.(iii) and (v)Why might an area with a large amount of limestone (CaCO3) be less susceptible to acid rain?
A) The acid in the rain is neutralized by the natural base in the limestone. B) The rain travels quickly through the porous limestone and therefore the rate of reaction is slower. C) Limestone is degraded by acid rain and therefore acid rain has the same damaging effects. D) Only acid rain made from sulfur compounds reacts with the limestone. E) none of the above
Based on the number of galaxies visible in the Hubble eXtreme Deep Field (Figure 20.1 in your text), the estimated number of galaxies in our observable universe is at least
A) 100 billion. B) 100 million. C) 50,000. D) infinity.