Supermassive black holes are believed to be located at the center of many galaxies because
a. the rotation curve of the galaxy indicates that 90% of the galaxy is dark matter.
b. the orbital motion of material near the center is very fast and indicates a very massive core.
c. the shape of the bulge in all spiral galaxies can only be supported by a supermassive black hole.
d. the spiral structure requires a black hole to maintain the spiral arms.
e. the orbital speeds of a globular clusters in the galaxy are greater than the speed of light.
B
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(a) Large parts in sea water, such as a ship hull (b) Catalytic converters (c) Human body implants (d) Satellite parts
Once there was a highly intelligent turkey that had nothing to do but reflect on the world's regularities. Morning always started out with the sky turning light, followed by the master's footsteps, which were always followed by the appearance of food. Other things varied, but food always followed footsteps. The sequence of events was so predictable that it eventually became the basis of the
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A sports car of mass 1000 kg can accelerate from rest to 72. km/h in 6.6 s. What would the average force of the car's engine be?
What will be an ideal response?
Two plane mirrors make an angle of with each other. A light ray enters the system and is reflected once off of each mirror. Through what angle is the ray turned?
A) 60° B) 90° C) 120° D) 150°