The pupil of the human eye is approximately 0.8 cm in diameter when adapted to the dark. The ratio of the light-gathering power of a 1.6-m telescope to that of the human eye is ____
a. 2
b. 4
c. 20
d. 400
e. 40,000
e
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A point charge Q is placed on the x axis at x = 2.0 m. A second point charge, ?Q, is placed at x = 3.0 m. If Q = 40 ?C, what is the magnitude of the electrostatic force on a 30-?C charge placed at the origin?
a. 7.2 N b. 3.9 N c. 1.5 N d. 14 N e. 8.1 N
The position of a 0.64-kg mass undergoing simple harmonic motion is given by x = (0.160 m) cos (pt/16). What is its position at t = 6.0 s?
a. 0.160 m c. 0.061 m b. 0.159 m d. 0.089 m
In twice the time, an object will fall
A) 16 times as far. B) 12 times as far. C) four times as far. D) twice as far. E) eight times as far.
Seismic waves are most useful for mapping
A) the surface of Mars with Global Surveyor. B) the surface of Venus with Magellan. C) the Earth's core and mantle. D) the depths of the oceans. E) the density of the hydrosphere.