Which of the following is true of O and B stars?
A) Their parallax is too small to measure.
B) They are not found in associations.
C) They reveal parts of six spiral arms near the Sun.
D) Their distances cannot be measured by spectroscopic parallax.
A
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Which of the following quantities is equal to the energy per second generated by fusion in the Sun's core?
A) the force of gravity holding the Sun together B) the temperature of the Sun's core C) the temperature at the Sun's photosphere D) the luminosity of the Sun's photosphere
According to current models, where does the element gold come from?
A) mergers of neutron stars B) the supernova explosions of high-mass stars C) the late stages of fusion in low-mass stars D) the Big Bang
In the hypothetical atomic interaction shown in figure C9.13, if the system had the appropriate total energy and initial position, could the atoms’ separation remain stable and constant?
A. No
B. Yes, at a separation of about 0.12 nm
C. Yes, at a separation of about 0.25 nm
D. Yes, at a separation of either about 0.12 nm or 0.25 nm
E. Yes, at some other separation(s) (specify)
A car wash nozzle directs a steady stream of water at 1.10 kg/s, with a speed of 30.0 m/s, against a car window. What force does the water exert on the glass? Assume the water does not splash back
a. 27.3 N b. 33.0 N c. 31.1 N d. 0.367 N e. 1.10 N