1. set the "dark matter" slider to 10%. take a "snapshot" of the motions. what shape do the points make
in the diagram at the upper right?
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2. how fast is the innermost star moving and what is its distance from the center?
3. how far from the center, is the next closest star? how fast is it moving?
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4. does the data you see follow the law of universal gravitation (1/sqrt(2) relationship)? explain your answer.
5. turn on the "show speeds" toggle. now increase the "dark matter" slider to 60%. that adds an extra 50%
to the mass of the galaxy, spread out roughly uniformly. what is the speed of the innermost star now?
what is the speed of the next closest star now?
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6. do these speeds now obey the 1/sqrt(2) relationship?
7. take a "snapshot" of the speeds. describe how the pattern of the marks on the graph changes.
8. turn on the "show speeds" toggle. set the "dark matter" slider to 100%. that adds an amount of dark
matter equal to the visible matter in the galaxy. what is the speed of the innermost star now? what is
the speed of the next closest star now?
9. take a "snapshot" of the speeds. what is the pattern of the marks now?