Which of the following statements about the disk of the Milky Way is generally true?
A) The typical age of disk stars is greater than that of halo stars.
B) Disk stars are all younger than 5 billion years.
C) Disk stars have a higher proportion of heavy elements, on average, than halo stars.
D) Disk stars orbit around the Galactic center in orbits of random inclination and direction.
E) The diameter of the disk is about 1 million times its thickness.
C) Disk stars have a higher proportion of heavy elements, on average, than halo stars.
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Sound: The speed of sound through the ground is about 6.0 km/s while the speed of sound in air is 343 m/s. A very powerful explosion occurs some distance away and you feel the ground vibrate 60 seconds before you hear the sound of the explosion. How far away is the explosion?
A. 20 km B. 22 km C. 25 km D. 27 km E. 30 km
According to our present theory of solar system formation, how did Earth end up with enough water to make oceans?
A) The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars. B) The water was mixed in the other materials in the planetesimals that accreted at our distance from the Sun. C) The water was formed by chemical reactions among the minerals in the Earth's core. D) Earth formed in the relatively narrow region of the solar nebula in which liquid water was plentiful.
Which of the following is considered "interplanetary matter"?
A) Titan B) Triton C) the Moon D) Ganymede E) Comet Hale-Bopp
A 3. kg ball of putty moving at 1 m/s collides and sticks to a 2 kg ball initially at rest. The putty and ball then move with a momentum of
A) 1 N-s. B) 2 N-s. C) 4 N-s. D) 3 N-s. E) 0 N-s.