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Devil physics The baddest class on campus Pre-IB Physics
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Giancoli Section 5-8 Satellites and “weightlessness”
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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.
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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’.
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Girl in Elevator FN Fg
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Girl in Elevator Elevator not moving Acceleration zero FN Fg
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Girl in Elevator Elevator moving up Acceleration Positive FN Fg
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Girl in Elevator Elevator moving down Acceleration Negative FN Fg
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Girl in Elevator FN Fg Elevator cable breaks
Girl plummeting to her death, but remains calm FN Fg
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Weightlessness Weightlessness on a Motorcycle Weightlessness on Skis
Motorcycle Jump Weightlessness on Skis Ski Jump Weightlessness in a Cage ?????
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Weightlessness and Space
How do you keep from losing satellites? ??? ???
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Weightlessness and Space
FG mac
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Weightlessness and Space
FG mac
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Weightlessness and Space
FG mac
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Weightlessness and Space
re
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Weightlessness and Space
FG mac
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Weightlessness and Space
What happens if we change speed? FG mac
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Weightlessness and Space
FG mac 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.
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Weightlessness and Space
FG mac 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.
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Weightlessness and Space
Only one speed for a given orbit (radius) Only one orbit (radius) for a given speed FG mac
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Space Away From Earth FG-Moon FG-Sun FG-Earth
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Gravitational Force and Motion of Planets
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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?
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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’?
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Questions?
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Homework #39-49
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