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Devil physics The baddest class on campus Pre-IB Physics. Giancoli Section 5-8 Satellites and “weightlessness”. Objectives . Calculate the radius of a satellite’s orbit given its height above the earth’s surface and the radius of the earth.
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Objectives • Calculate the radius of a satellite’s orbit given its height above the earth’s surface and the radius of the earth. • Understand that for any given velocity, there is only one distance from the center of the earth at which the satellite can remain in orbit. • Understand that for any given altitude, there is only one velocity at which the satellite can remain in orbit.
Objectives • Calculate the altitude at which a satellite must orbit for a given velocity. • Calculate the velocity at which a satellite must orbit for a given altitude. • Understand the meaning of ‘apparent weight’ and ‘apparent weightlessness’.
Girl in Elevator FN Fg
Girl in Elevator FN • Elevator not moving • Acceleration zero Fg
Girl in Elevator FN • Elevator moving up • Acceleration Positive Fg
Girl in Elevator FN • Elevator moving down • Acceleration Negative Fg
Girl in Elevator FN • Elevator cable breaks • Girl plummeting to her death, but remains calm Fg
Weightlessness • Weightlessness on a Motorcycle • Motorcycle Jump • Weightlessness on Skis • Ski Jump • Weightlessness in a Cage • ?????
Weightlessness and Space ??? • How do you keep from losing satellites? ???
Weightlessness and Space FG mac
Weightlessness and Space FG mac
Weightlessness and Space FG mac
Weightlessness and Space FG mac
Weightlessness and Space • What happens if we change speed? FG mac
Weightlessness and Space • If velocity increases, the force needed to keep the shuttle in orbit increases. Since the earth’s gravity doesn’t change, the shuttle will leave the circular orbit. FG mac
Weightlessness and Space • If velocity decreases, the gravitational force is now stronger than the radial acceleration and it will pull the shuttle toward the earth, which will increase gravitational force, and the shuttle will be pulled down to the earth’s surface. FG mac
Weightlessness and Space • Only one speed for a given orbit (radius) • Only one orbit (radius) for a given speed FG mac
Space Away From Earth FG-Moon FG-Sun FG-Earth
Σary Review • Can you calculate the radius of a satellite’s orbit given its height above the earth’s surface and the radius of the earth? • Do you understand that for any given velocity, there is only one distance from the center of the earth at which the satellite can remain in orbit? • Do you understand that for any given altitude, there is only one velocity at which the satellite can remain in orbit?
Σary Review • Can you calculate the altitude at which a satellite must orbit for a given velocity? • Can you calculate the velocity at which a satellite must orbit for a given altitude? • Do you understand the meaning of ‘apparent weight’ and ‘apparent weightlessness’?
Homework #39-49