The History of Astronomy

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5

Slide 36

The Universal Law of Gravity

Any two bodies are attracting each other through gravitation, with a force proportional to the product of their masses and inversely proportional to the square of their distance:

F = - G

Mm

r2

(G is the Universal constant of gravity.)

Slide 37

According to Newton’s universal law of gravity, the sun is attracting the Earth with a force of 3.6*122 N. What is the gravitational force that the Earth exerts on the sun?

1.75*118 N

3.6*122 N

1.95*129 N.

Depends on the relative speed of the Earth with respect to the sun.