ASTR 101 Lecture Notes - Lecture 17: Inverse-Square Law, Reduced-Gravity Aircraft, Weightlessness
20 Oct 2016
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Lecture 17 - weightlessness, mass, and exoplanets and tides. Iss is 5. 8% farther from centre of earth than we are, and force of gravity is 12% weaker (inverse square law), therefore it is not zero! Moon moves in its curved orbit because of earth"s gravity; shows that astronauts are not beyond earth"s gravity. Everyday terms: weight is our perception of a force acting on us (a reaction) Gravity pulling down on you with certain force. Scale and oor resist that with an equal and opposite force. Ex. imagine in an elevator, and someone snips the cable. Jumping out of airplane; you feel weightless, air resistance produces terminal velocity (no longer going faster) In water (ex. scuba diving) feels like weightlessness but you are not truly in weightlessness. In space, you feel the perfect sensation of weightlessness. Space station is constantly falling onto earth, yet orbiting the earth, so the astronauts feel weightless.
