PHYS 1000 Lecture Notes - Lecture 5: Ozone Depletion, Tidal Locking, Semi-Major And Semi-Minor Axes
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U(cid:396)fa(cid:272)e g(cid:396)a(cid:448)ity is the st(cid:396)e(cid:374)gth of the g(cid:396)a(cid:448)itatio(cid:374)al fo(cid:396)(cid:272)e o(cid:374) the (cid:271)ody"s su(cid:396)fa(cid:272)e. es(cid:272)ape speed is the speed (cid:396)e(cid:395)ui(cid:396)ed fo(cid:396) a(cid:374) o(cid:271)je(cid:272)t to es(cid:272)ape fo(cid:396)e(cid:448)e(cid:396) the (cid:271)ody"s g(cid:396)a(cid:448)itational pull. Tides are due to gravitational force on earth from moon force on near side of earth is greater than force on far side. The sun has less effect, but it does modify the lunar tides. We call this variation of the strength of a force across a body, a tidal force. This will lead to two sets of high and low tides each day. Ea(cid:396)th"s (cid:396)otatio(cid:374) d(cid:396)ags the tidal (cid:271)ulge (cid:449)ith it so that it is just ahead of the earth-moon line. The moons gravitational pull on this offset bulge will actually slow our planets rotation. The (cid:396)ate is a(cid:271)out (cid:1006) (cid:373)illise(cid:272)o(cid:374)ds a (cid:272)e(cid:374)tu(cid:396)y. Half a (cid:271)illio(cid:374) yea(cid:396)s ago ea(cid:396)th"s day (cid:449)as just o(cid:448)e(cid:396) (cid:1006)(cid:1005) hou(cid:396)s long and the year had 419 days.