Who invented the galaxy classes, and what three major groups did he invent?
What will be an ideal response?
Edwin Hubble divided the galaxies into S (spirals), E (ellipticals) and Irr (irregulars).
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Masses of the planets are easiest to determine if:
A) they are terrestrial and the extra size of the planet's disk can be measured. B) they are jovian and their oblateness can be found. C) they have natural satellites whose motions can be precisely measured. D) they are dense and easily deflect the path of passing spacecraft. E) they move rapidly and their periods are easily measured.
There appears to be a correlation between the 22-year solar cycle and:
A) droughts in North America. B) asteroid impacts on Earth. C) change of which political party has the majority in the U.S. Congress. D) the length of Mercury's day. E) the length of Saturn's year.
An automobile traveling along a straight road increases its speed from 30.0 m/s to 50.0 m/s in a distance of 180 m. If the acceleration is constant, how much time elapses while the auto moves this distance?
a. 6.00 s b. 4.50 s c. 3.60 s d. 4.00 s e. 9.00 s
A thin copper rod that is 1.0 m long and has a mass of 0.050 kg is in a magnetic field of 0.10 T. What minimum current in the rod is needed in order for the magnetic force to cancel the weight of the rod?
A) 1.2 A B) 7.6 A C) 2.5 A D) 4.9 A E) 9.8 A