Tidal Forces

(a) The Moon induces tidal forces, Ftide, on Earth. At each point, this force is the difference between the
force, Fout, created by the orbital motion of the two bodies around their barycenter, and the Moon’s gravitational
force, Fgrav, at that point. The magnitude and direction of each arrow represent the strength and direction of each
force. (b) Water slides along Earth to create the tides. Ignoring Earth’s rotation and the effects of the continents
until Figure 6-31, this figure shows how two high tides are created on Earth by the Moon’s gravitational pull. The Sun
has a weaker, but otherwise identical, effect.