In scattering processes involving moving objects an exchange of electromagnetic and mechanical power takes place. The problem is considered for arbitrary objects in one, two, and three dimensions. It is shown that the energy balance depends on the scattering amplitude, evaluated at the frequency of excitation, on this frequency itself, and on the velocity in question. Three cases are considered: objects moving in free space, objects moving together with the surrounding medium, and objects moving through a medium, at rest with respect to the observer. An interesting result is the fact that objects moving in the direction of the incident wave cause a loss of electromagnetic energy smaller than the gain occurring when the objects move in the opposite direction. This is a first-order effect in the velocity.