Using this approach to justify the electromotive force equation ( the precursor of the Lorentz force equation ), he derived a wave equation from a set of eight equations which appeared in the paper and which included the electromotive force equation and Amp�re's circuital law.

32.

The tidal force equation already accounts for the fact that Earth is not a point-particle; so you'd essentially be looking for the " additional " effect due to the fact that it is a non-point-particle whose axis of rotation is not identically parallel to the lunar orbital plane.

33.

For example, if you wanted to write an equation to calculate the " differential " tidal force due to the " diurnal libration " ( in other words, the " error " in the tidal force equation caused by the rotation of the Earth )-that effect would be very small.