When did oxygen begin to accumulate in the atmosphere?
A) as soon as Earth was formed
B) about 2 billion years ago
C) about 200 million years ago
D) as soon as the early bombardment ended
E) as soon as life appeared
B
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Mercury's orbital precession is adequately explained by Newton's Law of Gravity
Indicate whether the statement is true or false
Dark lines in an absorption spectrum represent:
a) particular energies of light coming from a distant object that areabsorbed by materialin between. b) flaws in the telescopes and spectroscopes that astronomers use to measure spectra. c) hotter regions in the object that is emitting the spectrum. d) regions where light travels more slowly and is not able to reach us. e) photons emitted when an electron jumps from a higher to a lower energy level.
Neutrinos are hard to detect because
A) they experience only the gravitational force. B) they move so fast. C) they experience only the weak force. D) they have such a small mass. E) All of the above.
A road bicycle racer rides down the highway from Pike’s peak. During one stretch of the ride, he descends 150 m while accelerating from 35 km/hr to some final speed. Assuming rolling friction and air resistance to be negligible, what is that final speed?
A. 113 km/h B. 118 km/h C. 148 km/h D. 169 km/h