The following appeared in Marilyn Vos Savant's "Ask Marilyn" column in PARADE magazine on Sunday, May 20, 2001. Some of her statements are true, while others are not. I have parsed her answer into a list of the five separate sentences for ease of identification. State which are true and which are false.
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The Reader's Question:
Earth's gravity holds spaceships in orbit, but the things inside them are weightless and float around. Why doesn't gravity have an effect inside?
--Jerry Mapes, city unknown
Marilyn's Answer:
Actually, it does--the same way it affects the spacecraft itself.
When a space shuttle is orbiting the Earth, the sum of the "downward" (gravitational) force and the "forward'' (inertial) force of the moving ship and its contents nearly equals zero.
So both the ship and its contents are in freefall, which makes everything weightless.
They stay in orbit while "falling'' (being pulled toward the Earth) because the inertial force (centrifugal force, in this case) of the moving vehicle is radial--away from the Earth.
A similar principle applies to the planets: All are in glorious free-fall while orbiting within the gravitational field of the Sun.
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