If the spiral density wave were the only thing producing spiral arms, it would be expected that
a. all spiral arms would be gas and dust free.
b. all galaxies would have only two smooth spiral arms.
c. the Milky Way would show and irregular pattern of short arms .
d. the Milky Way wouldn't have any spiral arms.
e. the halo component of the Milky Way would show spiral arms as well.
b
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A stunt pilot performs a circular dive of radius 800 m. At the bottom of the dive (point B in the figure) the pilot has a speed of 200 m/s which at that instant is increasing at a rate of 20 m/s2. What acceleration does the pilot have at point B?
?
?
a.
m/s2
b.
A __________ does not interact via the strong interaction
Fill in the blank(s) with correct word
Force on a Wire: If a calculated quantity has units of 
, that quantity could be
A. an electric field. B. an electric potential. C. ?0. D. a magnetic field. E. a magnetic torque.
The combined mass of a binary system is three solar masses. Star A is 1 AU and Star B is 2 AU from the center of mass. What are the masses of Star A and Star B, respectively?
a. 2.5, 0.5 b. 1, 2 c. 2, 1 d. 0.5, 2.5