Question

. It is often said the astronauts are "weightless" in orbit. Indeed the amount of gravity will decrease as the astronauts are moved farther from earth. Does it diminish to the extent that it can be dismissed as insignificant? Compare for an astronaut with mass 75.0 kg. (b) Find the magnitude of the force of gravity upon them while aboard the shuttle in orbit 525 km above the earth. (c) The astronauts are not really “weightless” if by that we mean there is no gravity. So why do they appear to “float” around inside the space shuttle? Explain using physics

Answer 1

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Answer 2

...?

Answer 3

First, find the force of gravity on the astronaut using Newton's law of universal gravitation:

\[F={Gm_1m_2 \over r^2}\]
Your value for F will not be 0, indicating that that the astronauts still have some weight, although it will be smaller than their weight on the surface of the Earth.

So clearly the astronauts aren't weightless as the question says. Rather, they are in a form of free fall because they are ORBITING the Earth (with the force of gravity being the centripetal force). Because the astronaut is (roughly) moving in a circle, the acceleration of the astronaut is radially inward, rather than say left or right. Because the space shuttle the astronaut's in is subject to the same centripetal force, the astronaut doesn't move RELATIVE to the shuttle, but clearly moves RELATIVE to the Earth.

Answer 4

thank you! I think I got it.