The Potential and its Relation to Masses

Now we establish the relation between the potential U and masses. First, consider an elementary mass dm — 8dV. In accordance with Equation (1.8) we have 

Comparing Equations (1.39 and 1.47) we can conclude that the function U, corresponding to the field of the elementary mass located at the point q, is 

applying the principle of superposition, we arrive at an expression for the potential caused by a volume distribution of masses  

Equations (1.6 and 1.50) clearly show that the potential is related to masses in a much simpler way than the field g, and this is the second reason for its introduction. Along with volume masses, it is possible to introduce other types of masses, and we have 

It is useful to discuss one more application of the potential, and with this purpose in mind we consider the change of this function, dU in the vicinity of some 

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