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thecommexokid
- 70
- 2
"Gravitational field" vs. "acceleration due to gravity"
So I'm pretty sure the following paragraph is all true. Do the citizens of PhysicsForums agree? Please confirm and/or correct and/or clarify, as needed.
In electostatics, the electric field E is a completely different quantity than the acceleration due to an electric force aE, which you could calculate as aE = qE E / m (where qE E is the electric charge). But the gravitational field Φ and the acceleration due to gravitational force aG are the same thing. By analogy with the electric case, aG = qG Φ / m, but qG, the "gravitational charge", is itself just m. So it all comes down to the familiar fact that inertial mass and gravitational mass are the same thing...which is an unexplained coincidence in the context of Newtonian mechanics (though it possibly has firmer footing in general relativity).
So I'm pretty sure the following paragraph is all true. Do the citizens of PhysicsForums agree? Please confirm and/or correct and/or clarify, as needed.
In electostatics, the electric field E is a completely different quantity than the acceleration due to an electric force aE, which you could calculate as aE = qE E / m (where qE E is the electric charge). But the gravitational field Φ and the acceleration due to gravitational force aG are the same thing. By analogy with the electric case, aG = qG Φ / m, but qG, the "gravitational charge", is itself just m. So it all comes down to the familiar fact that inertial mass and gravitational mass are the same thing...which is an unexplained coincidence in the context of Newtonian mechanics (though it possibly has firmer footing in general relativity).
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