Why do physicists care about electrical potential?

[member 392791]

So I was thinking, I never heard about gravitational potential, yet there is such a big deal about electrical potential. Why is it so much more important that voltage be taught, yet no mention of its gravitational analog?

 

[WannabeNewton]

You are highly mistaken; the concept of gravitational potential is EXTREMELY important and the field theoretic formulation of Newtonian Gravity has its basic equations in terms of the gravitational potential: \mathbf{a} = -\triangledown \Phi, \triangledown ^{2}\Phi = 4\pi G\rho. What level of physics are you studying currently? It is possible that at the high school level you might not have used gravitational potential all that much yet; wait until you start talking about conserved systems and you will see it come up (the good old mg\Delta y).

 

[e.chaniotakis]

Well, to me in electromagnetism that I know better than G.R,
-potential is easier to calculate than the electric field. You obtain the potential and by a simple differentiation you find the field.
-it describes physics more fundamentally.

 

[ZapperZ]

So I was thinking, I never heard about gravitational potential, yet there is such a big deal about electrical potential. Why is it so much more important that voltage be taught, yet no mention of its gravitational analog?

1. There's a lot more "interesting" geometry with respect to the electric potential than with gravitational potential. This is because there are simpler and clearer boundary conditions and source distribution of varying geometries that can be imposed for the electric potential than with gravitational potential. While one can also impose some interesting mass distribution for gravitational potential, in realistic situations, this are seldom encountered when compared to our ability to have many different configurations of charge sources and boundary condition.

2. On the other hand, we ARE concerned about gravitational potential. If you have done Lagrangian/Hamiltonian/least action mechanics, practically ALL of the problems you have to deal with involves gravitational potential. The Brachistochrone problem is a common example.

Zz.

 

[yungman]

I don't know mechanical physics, I cannot comment on gravitational potential and all, don't even know the meaning.

Remember, electric potential is something you can measure easily...VOLT! This is something we electrical people measure everyday, all day. We don't go out and measure electric field and in a lot electronics, we don't deal with field at all.

 

[member 392791]

Admittedly my post was ignorant. I was unaware that gravitational potential was important at a more advanced treatment of physics, which is why I wondered why it was something completely skipped in an introductory physics sequence, even though the electrical analog is discussed in much greater detail.

Just because the pedagogy leads itself to comparing gravity with electric fields. It's like why the gravitational version of gauss's law is not discussed until the electrical analog is first.

 

[WannabeNewton]

Gravitational potential is certainly not skipped in introductory classes. It is taught extensively when doing conservation of energy problems. How did you do problems that involved things like stability of cubes resting on cylinders and things like that without gravitational potential? Heck even things like springs hanging from a ceiling, a marble rolling in a dish, the circular pendulum, the inverted pendulum, the double pendulum, and the spherical pendulum are treated using gravitational potential granted you probably won't see the double pendulum or the spherical pendulum in an introductory class but certainly the others. In my AP Physics C class we also did calculation of gravitational potentials for various mass distributions (e.g. finite rod, infinite rod, spherical volume with cavity things like that).