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over any location on the surface of Earth? Why or why not? – Page 1 of 3 – 4. Assuming that most stars and gas in the disk of our Galaxy are in nearly circular
orbits and the fact that the centripetal force holding that material in a circular path
is Newton’s gravity, verify that the expression
M (< R) =
relates the mass enclosed within a given radius R to rotational velocity of the
stars/gas V at that radius is reasonable. NOTE: You will need to assume that the
mass distribution is spherically symmetric such that you can treat all the mass
within the orbit as residing at the center of the orbit. This is the typical
assumption in gravitation problems, that you treat all the mass as lying at the
center of mass. There is no need to prove this theorem since Carroll and Ostlie
provide the proof in Section 2.2).
5. The International Astronomical Union (IAU) has recommends values for the
Sun’s distance from the center of the Milky Way galaxy of 8.5 kiloparsecs and the
Sun’s orbital speed around the galaxy of 220 km/s 1. Use these values to estimate
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This document was uploaded on 03/04/2014 for the course ASTROPHYS 362 at Minnesota State University Moorhead .
- Spring '14