Which of the following provides evidence for the existence of dark matter?
A. The orbital speeds of galaxies in clusters are higher than what can be accounted for by the detectable mass of the cluster.
B. the ability of rich galaxy clusters to prevent their hot gases from expanding
C. The orbital speeds of stars in galaxies are higher than what can be accounted for by the detectable mass in the galaxy.
D. All of these choices are correct.
Answer: D
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The index of refraction for red light in water is 1.331 and for blue light is 1.340. If a ray of white light enters the water at an angle of incidence of 83.00°, what are the underwater angles of refraction for the blue and red components of the light?
What will be an ideal response?
An astronaut floating in the International Space Station catches a Frisbee thrown directly toward his or her center of mass. Does the astronaut + Frisbee’s change in thermal energy ?Uth depend on whether the Frisbee is spinning or not, and if so, which case makes it larger?
A. ?Uth is greater if the Frisbee is spinning. B. ?Uth is the same in both cases. C. ?Uth is greater if the Frisbee is not spinning. D. One needs more information to tell.
The product of the wavelength times the frequency of a wave is its ________
Fill in the blank(s) with correct word