Gravitation

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5

Slide 41

Why the Moon?

Since the Sun is much farther from Earth than the Moon, the difference in distance across Earth is much less significant for the Sun than the Moon, therefore the difference in gravitational force on the two sides of Earth is less for the Sun than for the Moon (even though the Sun’s force on Earth is more).

Slide 42

Why the Moon?

The Sun does have a small effect on Earth’s tides, but the major effect is due to the Moon.