According to fossil evidence, how far back in time did life on Earth exist?
A) about 545 million years B) about 2.0 billion years
C) about 65 million years D) about 3.5 billion years or more
D
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Heisenberg's thought experiment to determine the location of an electron is illustrated here. Why don't we observe the effects of the uncertainty principle in our macroscopic world?
a. The uncertainty principle is turned off in the macroscopic world. b. We never want to know both an object's momentum and its position at the same time. c. Because of the smallness of Planck's constant. d. Because the deBroglie wavelengths of macroscopic objects are too large. e. Because the relativistic principles of Einstein apply instead.
Besides Earth, which of the terrestrial planets and/or their satellites show(s) evidence for the possible existence of liquid water flowing on its surface in the past?
What will be an ideal response?
The planet Venus requires 225 days to orbit the Sun, which has a mass M = 1.99 × 1030 kg, in an almost circular trajectory. Calculate the radius of the orbit and the orbital speed of Venus as it circles the Sun.
What will be an ideal response?
The percentage (by number of atoms) of the Sun that is hydrogen is about
A) 91%. B) 71%. C) 27%. D) 9%. E) less than 1%.