What do we mean when we say that the rotation curve for the Milky Way Galaxy is "flat"?
A) Gas clouds orbiting far from the galactic center have approximately the same orbital speed as gas clouds located further inward.
B) The amount of light emitted by stars at different distances is about the same throughout the galaxy.
C) The disk of a spiral galaxy is quite flat rather than spherical like the halo.
D) All the galaxy's mass is concentrated in its flat, gaseous disk.
A) Gas clouds orbiting far from the galactic center have approximately the same orbital speed as gas clouds located further inward.
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If a convex lens were made out of very thin clear plastic filled with air, and were then placed underwater where n = 1.33 and where the lens would have an effective index of refraction n = 1, the lens would act in the same way
a. as a concave mirror in air. b. as a concave lens in air. c. as a convex lens in air. d. as a flat refracting surface between water and air as seen from the water side. e. as the glasses worn by a farsighted person.
Your friend left your house and has been driving 60 miles per hour the whole time since then, and has gone 30 miles. How long has she been driving?
A) 30 minutes B) 60 minutes C) 2 minutes D) 1800 minutes E) 1/2 minute
The point in time when the expansion of the universe began is referred to the
A) big crunch B) cosmic detonation event C) big bang D) big blowup
In the Eagle nebula a shock wave crashes into colder, dark gas. What does this cause?
a) formation of large amounts of dust made of carbon and silicon b) causes no stars to form in the region for about 500,000 years c) causes a reflection nebula d) compression of gas and star formatione) destruction of all Bok globules