**Gravitational Force Between Two Bodies:**

Newton’s law of gravity states that the gravitational force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them.To know more about Gravitational Force Between Two Bodies,watch Gravitational Force Between Two Bodies Video to learn more .

The Universal Gravitation Equation is:

**F = GMm/R ^{2}**

where

**F**is the force of attraction between two objects in newtons (N)**G**is the Universal Gravitational Constant = 6.674*10^{−11}N-m^{2}/kg^{2}**M**and**m**are the masses of the two objects in kilograms (kg)**R**is the separation in meters (m) between the objects, as measured from their centers of mass

**Force attracting Earth and Moon**

To calculate the gravitational force pulling the Earth and Moon together, you need to know their separation and the mass of each object.

**Distance**

The Earth and Moon are approximately 3.844*10^{5} kilometers apart, center to center. Since the units of **G** are in meters, you need to change the units of separation to meters.

**R** = 3.844*10^{8} m

*Mass of each object*

Let **M** be the mass of the Earth and **m** the mass of the Moon.

**M** = 5.974*10^{24} kg

**m** = 7.349*10^{22} kg

**Force of Attraction**

Thus, the force of attraction between the Earth and Moon is:

**F = GMm/R ^{2}**

**F = **(6.674*10^{−11} N-m^{2}/kg^{2})(5.974*10^{24} kg)(7.349*10^{22 }kg)**/**(3.844*10^{8} m)^{2}

**F** = (2.930*10^{37 }N-m^{2})**/**(1.478*10^{17} m^{2})

**F** = 1.982*10^{20} N

**Note:** Notice how all the units, except N, canceled out.

Attraction between Earth and Moon

*Result of force*

This considerable force is what holds the Moon in orbit around the Earth and prevents it from flying off into space. Inward force of gravitation equals the outward centrifugal force from the motion of the Moon.

Useful for CBSE, ICSE, NCERT & International Students

Grade :9

Subject : Physics

Lesson : Gravitation

Topic:Gravitational Force Between Two Bodies Video

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