Approximately how long after the Solar System formed did it take for oxygen to get to within 80 percent of its present abundance in Earth's atmosphere?
a. 4 billion years
b. 1 billion years
c. 400 million years
d. 1 million years
e. Oxygen was always a primary component of Earth's atmosphere.
a. 4 billion years
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Two men, Joel and Jerry, push against a wall. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do
A) Both men do positive work, but Joel does 75% more work than Jerry. B) Both men do positive work, but Joel does 50% more work than Jerry. C) Both men do positive work, but Jerry does 50% more work than Joel. D) Both men do positive work, but Joel does 25% more work than Jerry. E) Neither of them does any work.
It is diffraction that limits the ________ of a telescope of a given objective diameter
A) magnification B) light grasp C) interference D) aperture E) resolution
Work done by STATIC FRICTION is always
A) along the surface. B) perpendicular to the surface. C) positive. D) negative. E) zero.
A 100-W light bulb is left on for 8.0 hours. Over this period of time, how much energy was used by the bulb?
a. 8.0E+2 J b. 2.9E+5 J c. 2.9E+6 J d. 1.34 hp e. 2.9E+4 J