Final exam practice questions

Here are my answers to the practice questions. Please let me know if you have questions or spot any mistakes! Don't forget to post requests for review topics by commenting either here or in the previous post.

1.  a,b
2.  e
3.  a
4.  e
5.  1/5 or 0.2
6.  A-D are all "neither."
7.  a shorter; more
8.  b, c
9.  A is twice as far away.
10.  d, e
11.  c
12.  1/40 c = 7.5 x 10^6 m/s away from the second observer and toward the first
13.  The black hole. By definition its escape speed is higher than c.
14.  f > c > a = b > d > e
15.  e (I originally said c, which was incorrect!)
16.  d
17.  a
18.  I got a radius of about 3 m, the height of a basketball hoop off the floor. (Note I originally said 2 m, which was a mistake. Also be aware that I had a typo in the question at first: the number given is the mass of Jupiter, not the Sun. I have now updated the file on Blackboard.)

Good luck with your studying!