A common 5-L metal can will float in air if it is
A) evacuated of air.
B) filled with a very large amount of helium.
C) thrown high enough into the air.
D) Nonsense! Unless the can and displaced air weigh the same, the can can't float in air.
Answer: D
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The Earth exerts a gravitational force on a person standing on the surface. The person also exerts a gravitational force on the Earth. Based on Newton's third law of motion, how do these two forces compare?
A) The forces exerted by the Earth and the person are the same. B) The Earth exerts a much stronger force than the person. C) The person exerts a much stronger force than the Earth. D) The Earth exerts a slightly stronger force than the person. E) The person exerts a slightly stronger force than the Earth.
The mean free path of molecules in a gas is proportional to:
A. the molecular diameter B. the reciprocal of the molecular diameter C. the molecular concentration D. the reciprocal of the molecular concentration E. the average molecular speed
The ________ habitable zone is set by the activity of the nucleus on the inside, and the rate of star formation and proper chemistry on the outside
Fill in the blank(s) with correct word
Which of the following transitions within an atom is not possible?
A) An electron begins in an excited state and then gains enough energy to jump to the ground state. B) An electron begins in the ground state and then gains enough energy to jump to an excited state. C) An electron begins in the ground state and then gains enough energy to become ionized. D) An electron begins in an excited state and then gains enough energy to become ionized.