Midterm Solutions

# 1 page 2 of 16 physics 160 fall 2013 midterm exam

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Unformatted text preview: the center of our Galaxy (in solar masses): 4x106 (e) Resolution of the eye (in arcseconds): 60 (f) Fraction of the Sun’s mass lost due to fusion over 1010 yr (in %): L/c2 = 4e26W/(3e8m/s)2 ≈ 4e9 kg/s x πe7 s/yr x 1e10 yr ≈ 1e27 kg ≈ 10 ­3 Msun so 0.1% Page 2 of 16 Physics 160 Fall 2013 Midterm Exam (2) [20 pts] Were you paying attention? Short Answers Answer each of the following (4 pts each); you do not need to show your work. Question (b) refers to letters written on the chalkboards. (a) What is the current Sidereal Time? At 2:30pm (4:00pm) on 10/31, it will be 16:21 (17:51). You can estimate by remembering that in Week 1 LST midnite was 0:00, so 2:30pm would have been 14:30. However, 4 weeks have passed, which is roughly a month, or 2 hours of sidereal motion. (b) Which of the letters on the boards corresponds to an azimuth of 90º? It will be the one pointing due East – A, B o...
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## This document was uploaded on 02/26/2014 for the course PHYS 160 at UCSD.

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