10
More on
tides
1.Tidal friction leads to energy loss.
2.Earth’s rotation drags the tidal bulge forward, helping pull the moon (its orbit is increasing in
radius).
3.The energy comes from Earth’s rotation, which is slowing.
4.The extraction of energy from the moon’s rotation led to phase-locking.
Tidal forces will
appear later in the semester in other astrophysical contexts. Watch for them.