How does the earth exert gravitational pull on the sun

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Homework Help Overview

The discussion revolves around the gravitational interaction between the Earth and the Sun, specifically questioning the validity of the statement that the gravitational pull exerted by the Earth on the Sun is equal to that exerted by the Sun on the Earth.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster expresses confusion regarding the equality of gravitational forces between the Earth and the Sun, prompting participants to reference Newton's third law and suggest comparing the forces directly.

Discussion Status

Participants are exploring the concept of gravitational forces, noting that while the forces are equal, they act on different masses. Some have provided insights into the formula for gravitational force and the dependence of acceleration due to gravity on the mass of the respective bodies.

Contextual Notes

There is a lack of equations provided by the original poster, and some participants have pointed out the importance of understanding the relationship between mass and gravitational force in this context.

ASidd
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Homework Statement



My physics teacher today said that the Earth exerts the same amount of gravitational pull on sun;as the sun exerts on the earth.
Is this really true?

Homework Equations



There is no equation.

The Attempt at a Solution


I am very confused with this. How can the Earth's gravitational pull equal that of a massive body like the sun?
Can somebody explain this to me please?
 
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Think about Newton's third law.
 
Why don't you work out the 2 forces and compare them?
 
The forces are equal but acting on different masses.
 
The force between two bodies is.. GmM/r2

where m and M are the two masses and r the distance between them. Note how the force depends on both masses not just that of one of them.

The acceleration due to gravity is only dependent on the mass of one body..

F = GmMr2
F = mg
so
gm = GmMr2
mass cancels
g = GMr2

So g on the surface of the Earth or sun depends only on the mass of that body not the mass of both.

The acceleration due to gravity on the surface of each is roughly..

Earth = 9.81 m/s2
Sun = 275 m/s2
 
CWatters said:
The force between two bodies is.. GmM/r2

F = (GmM)/r2
F = mg
so
gm = (GmM)/r2
mass cancels
g = (GM)/r2
A little typo there. And G is gravitational constant.
 
Oi who's been stealing my / I'm sure they were there earlier :-)
 

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