L13 (spirals)

Question 1

5.5 SPIRALS IN LECT NOTES (NEW)

Answer 1

C

Question 2

newton laws

Answer 2

I: gravitational force inside a spherical shell of uniform density is zero ( the potential must be constant within the shell.)

II: outside any spherically symmetric object, the gravitational force is the same as if all its mass had been concentrated at the center

Question 3

why diff rotation in spiral arms?

Answer 3

x