ERTH 2403 Lecture Notes - Lecture 8: Tractive Force, Tidal Acceleration, Wave Height
26 Oct 2018
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Document Summary
Gravitational attraction of moon & sun & earth: 2. Ideal model (not reality: water-covered earth, spins frictionless under ocean, assumes no continents, (cid:1006). Lapla(cid:272)e"s dy(cid:374)amic theory: real, accounts for friction, and continents, 1. Gravity: pulls earth and moon together: 2. Inertia (centrifugal force): keeps them apart (prevents them crashing into each other, balances out gravity: 3. Earth rotates every 24hours, moon revolves around earth every 24 hrs 50 min: 2. Monthly, moon moves from 28 above earth"s equator to 28 below: 3. Moon orbit about earth elliptical: apogee farthest distance (from moon), lower tides, perigee closest distance (to moon), higher tides, solar tides, 1. Much weaker tractive force than the moon: 2. Sun moves 23 0 above and below earth"s equator annually: 3. Earth orbit around sun is elliptical: aphelion farthest distance (from sun), lower tides, perihelion closest distance (to sun), higher tides, sun and moon acting together, 1.
