Suppose two neutron stars or two black holes are closely orbiting one another. What do scientists predict will eventually happen to them, and why?
A) Their orbits will spiral inward until the two objects merge because of energy lost through gravitational waves.
B) Their orbits will gradually grow larger because of the centrifugal force involved as they circle around each other.
C) Their orbits will spiral inward as a result of friction with the surrounding gas until all the gas clears, after which their orbits will remain stable.
D) The orbits would remain stable unless there were a third object orbiting along with them.
A) Their orbits will spiral inward until the two objects merge because of energy lost through gravitational waves.
You might also like to view...
All the following statements about known extrasolar planets are true. Which one came as a surprise to scientists who expected other solar systems to be like ours?
A) Some of the planets orbit their star more closely than Mercury orbits the Sun. B) Most of the planets are quite massive—much more like Jupiter than like Earth. C) Most of the planets orbit stars that are quite nearby compared to the scale of the entire Milky Way Galaxy. D) In some cases, we've found more than one planet orbiting the same star.
Based on current evidence, how does the actual average density of matter in the universe compare to the critical density?
A) The actual density, even with dark matter included, is less than about a third of the critical density. B) If we include dark matter, the actual density equals the critical density. C) The actual density of dark matter and luminous matter combined is no more than about 1% of the critical density. D) The actual density of matter is many times higher than the critical density.
A 0.50 kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the mass is at the highest point of the circle the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?
a. 21 N b. 11 N c. 16 N d. 26 N e. 36 N
Magnets may be found only
a. in natural domains in the environment where there is magnetite. b. in pieces of all metals. c. in domains. d. where there are electric outlets. e. where there are aligned domains in a material.