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.