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Unformatted text preview: igid) moves up and down about 0.4 meter peak-to-peak twice a day!
Spring 2006 5 UCSD: Physics 8; 2006 Tidal friction makes the moon's orbit grow http://spiff.rit.edu/classes/phys235/no_moon/no_moon.html The bulge is carried forward by rotation (via friction), producing a gravitational "carrot" after which the moon races, gaining orbital energy and thus expanding the orbit by 3.8 cm per year Spring 2006 6 UCSD: Physics 8; 2006 The Sun is a Player Too The M/r3 ratio for the sun is 45% that of the moon When earth, moon, and sun are aligned (new moon, full moon), the tides add called spring tides When 90 out of phase (first quarter, last quarter), they partly cancel called neap tides moon dominates, so high tide still along earth-moon direction
deceptive view: should be polar view of earth Spring 2006 7 UCSD: Physics 8; 2006 San Diego full moon last qtr new moon 1st qtr Hawaii Spring 2006 8 UCSD: Physics 8; 2006 Tidal Resonance In Hawaii, the tides are less than a meter peak-to-peak representing the natural size of the bulge On a continental shelf, can get greater amplitude due to "sloshing" behavior 8 ft (2.5 m) peak-to-peak in San Diego Some inlets (Puget Sound, Bay of Fundy) experience resonance if natural "slosh" time has a 12-hour period, can get substantial amplification greater than 10 m peak-to-peak in some special locations Spring 2006 9...
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