Vision Problems: A little known fact is that both Robinson Crusoe and Friday wore eyeglasses. As it so happens, Robinson Crusoe was farsighted while Friday was nearsighted. Whose eyeglasses did they use whenever they wanted to start a fire by focusing the sun's rays?
A. Robinson Crusoe's
B. Friday's
C. Both would work equally well.
D. Both actually worked, but Friday's was a little bit better.
E. Neither's worked, but fortunately they were in possession of matches.
Answer: A
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Suppose I push a block along a tabletop at a constant velocity. If I exert a constant forward force of 
on the block and push it through a distance D, I do work on the block equal to ?F?D. Since the block’s kinetic energy does not change, friction must be exerting a backward force on the block of the same magnitude as 
(so that the net force on the block is zero, as required to maintain the block’s constant velocity). What work does the friction force do on the block?
A. No work
B. ? 
D
C. + D
D. Some negative work, but we need more information to determine exactly how much.
E. Some positive work, but we need more information to determine exactly how much.
The Sun exerts a greater gravitational force on the Earth than the moon does, yet the moon is primarily responsible for the tides, why is this so?
A. Nonsense, the moon is closer, so the gravitational force it exerts is stronger than the Sun’s. B. Nonsense, the Sun is responsible for the tides C. Tides are only created when the Sun and moon line up D. Because the variation of the gravitational force on the different sides of the Earth is greater due to the moon’s shorter distance from Earth.
A "fuzzy" dark or light patch in the sky is called a:
A) nebula. B) cloud. C) galaxy. D) comet. E) dust lane.
A turbogenerator produces
A) energy. B) power. C) neither, but transforms energy from one form to another. D) none of the above