ppt9 part1

ppt9 part1 - Tides Chapter 9 Prof. Weatherly Today:...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Tides Chapter 9 Prof. Weatherly Today: Equilibrium theory of tides (Completely ocean covered earth) Explains ●2-tidal bulges ●spring/neap tides ●diurnal tides/semidiurnal/mixed tides
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Tides result from astronomical effects: gravitational attraction of moon & sun AND centripetal acceleration of earth-moon & earth-sun rotating about their centers of mass.
Background image of page 2
First consider earth-moon. Earth and moon rotate about their center of mass – the barycenter. The earth spins about the barycenter and the oceans experience a centripetal acceleration.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What keeps the ball going around is the string. What keep the earth spinning around the barycenter is the gravitational attraction of the moon.
Background image of page 4
The centripetal force (the red arrows) is every where the same. The red arrows are all the same length and point in in the same direction.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
At earth’s center centripetal force = G M moon /r 2 (G=gravitational constant, M moon = mass of moon, r = distance from earth center to moon center) = the gravitational force of the moon.
Background image of page 6
On the other hand, the gravitational force of the moon (the black arrows) varies in strength and direction.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The gravitational force is largest on the side closer to the moon and least on the side furtherer from the moon. The force is always directed toward the center of the moon.
Background image of page 8
The tidal generating force (blue) is the difference of the moon’s gravitational force (black) and the centripetal force (red).
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The tide generating forces are shown again here, but now they are black. At Z
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 29

ppt9 part1 - Tides Chapter 9 Prof. Weatherly Today:...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online