What is Gravitational Potential and How Does it Vary with Distance?

[chocofingers]

Hello everyone, :)

I have yet another queries in physics.

What actually is gravitational potential ? I know the definition that it is the work done in bringing unit mass from infinity to the particular point. But I don't understand what actually it means...
Plus the definition of gravitational potential ... gravitational potential = - (GM/r^2) Now what's the importance of negative sign in this definition...

Plus where is the G.potential maximum and how does it vary with distance from centre of Earth to the surface of Earth and beyond it ?

I am an A-level student giving physics from CIE board so please explain me with in these limits ... ANy extra info is very well appreciated...

Thankz in advance :)

 

[chocofingers]

nobody knows about gravitational potential :S... Anybody /??

 

[harrylin]

Wikipedia is a good starting point:

http://en.wikipedia.org/wiki/Gravitational_potential

It 'represents the work (energy) per unit mass as an object moves to that location from a reference location'.

As the potential to do work increases with distance, what potential should infinite distance have? It was decided to define that potential as zero and the negative sign is then required to make the potential high up more than close to the Earth.

For an older related discussion of gravity inside the Earth, see
https://www.physicsforums.com/showthread.php?t=207148

 

[granpa]

first start with the potential of electric fields.
its simpler.

http://en.wikipedia.org/wiki/Energy_density#Energy_density_of_electric_and_magnetic_fields

 

[chocofingers]

thank you

 

[Knightycloud]

Hello everyone, :)

Plus the definition of gravitational potential ... gravitational potential = - (GM/r^2) Now what's the importance of negative sign in this definition...

and it's not r^2, it's r! :D

-\frac{GM}{r}

And the minus thingy is Gravitational force is always an attraction force. So it's minus. That's one explanation. There's another. It is generally considered the potential at infinity is zero and when to move a mass to another mass from that infinity point which is imaginary, that other mass do the work to pull.