There are niche heterodox subfields of economics that literally are just a dubious physics analogy (thermoeconomics), but the source's argument that marginal utility theory was copying von Hemholtz is the sort of extraordinary claim that requires extraordinary evidence, not zero citations, baffling confusion of economist Francis Edgeworth with literary writer Maria Edgeworth and a lot of tacked on claims that are laughably false (Jevons certainly didn't believe that "natural resources are inexhaustible: he was actually initially famous for trying to predict when the coal supply would run out!).

There are obvious reasons for studies of how money is spent to involve mathematics (though Menger managed to deduce marginal utility theory from first principles without equations) and it's unsurprising some of the equation forms superficially resemble some of the many simple equations of physics. There are much better criticisms of neoclassical economics and the application of neoclassical economics than accusing the early economists of plagiarising another field!