The most efficient form of locomotion in the animal kingdom is

A) a human walking.
B) a human on a bicycle.
C) a propeller-driven airplane.
D) a bird flying.
E) railroad trains.


B

Physics & Space Science

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A. 39% B. 49% C. 59% D. 79%

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In order for a substance to sustain a fission chain reaction, one important condition is that

A) each fissioning nucleus must release a sufficient number of neutrons. B) the nuclei must collide with enough energy to overcome the electrical repulsion between them. C) each fissioning nucleus must release a sufficient number of alpha-particles. D) energy must be continually supplied from the outside. E) the nuclei must stay in shape by maintaining a regular jogging program.

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In which of these v versus t graphs is the acceleration changing?

A. (a)
B. (b)
C. (c)
D. (d)

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If the magnitude difference between one star and another is 8, the stars differ in brightness by a factor of

a. 2.51. b. 20. c. 7. d. 1580.

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