Center-of-mass corrections to static properties of hadrons in the bag model

Various approaches to center-of-mass corrections are critically reconsidered and possible sources of inconsistencies are indicated. A specific method of calculation is advocated. Corrected values of masses, magnetic moments, axial-vector coupling constant $g_A$, and electromagnetic radii are expressed in terms of a single parameter $〈\frac{1}{\gamma }〉=〈{(1-v^2)}^{\frac{1}{2}}〉$.