The explanation of the Trouton–Noble experiment revisited

One class of explanations of the null result of the Trouton–Noble experiment uses the "standard" definitions of electromagnetic energy and momentum but is quite complicated. Another class is much simpler but appears to require new definitions of electromagnetic energy and momentum. We reconcile the two sets of explanations and show that they are both physically correct. We use the same arguments that have been used in discussions of the famous "4/3" factor in the electromagnetic mass of the classical electron.