Problem set 9 for ASTR 202: Stars, Galaxies and the Universe

Due in class, Thurs Nov 2

Textbook Chapter S2:

Review questions 8, 10, 11

Quick quiz question 27

Textbook Chapter S3:

Review questions 8, 15

Test Your Understanding problems 21, 24, 25, 29

Textbook Chapter 18:

Review questions 12 (you may find the Kip Thorne reading useful here), 13

Extra credit questions:

(1) By reading Kip Thorne's prologue, explain what the major differences are between smallish (10 solar masses) and large (several million solar masses) black holes, from the point of view of a spaceship that wants to study them as directly as possible.

(2) (needs some calculus) The tidal force on an object measures the amount that the force changes over a given distance. If you want to investigate a black hole with the same mass of the Sun (whose Schwarschild radius is 3 km), what is the difference in acceleration felt by your head and your feet, if you are 2 meters high, at a distance of 30 km from the black hole? (Hint: calculate dg/dr for Newton's law of gravity.) Do you think you would survive this standing up? Lying down?