A coupled sea ice-ocean model is used to examine the relative magnitudes of terms in the sea ice momentum equation, for ice concentrations less than 100%. This numerical model for steady state, horizontally homogeneous flow includes two terms that have previously been neglected in such quantitative models. These are oceanic form drag and wave radiation pressure, both of which are lateral forces that act on the side of floes. The former is generally decelerative, while the latter is accelerative. The model accepts as input variables average ice draft, areal concentration, and floe diameter. It is found that form drag can be greater than or of the same order as skin friction drag for small, thick floes at low concentrations. An exception to this rule occurs when the effect of wakes between floes reduces the local form drag. The higher net drag that generally exists at low concentrations implies lower ice floe speeds. Wave radiation pressure is negligible in all cases, although this is sensitive to our choice of fetch parameterization. Ocean drag is often parameterized in numerical models of sea ice as a skin friction term alone, with a constant drag coefficient between ice and (prescribed) geostrophic current velocities. Results from the present model are plotted in terms of such a drag coefficient, which is a function of concentration, floe size, and draft. This could be useful in future work where floe size data become regularly available, for instance, from radar satellite imagery. ¿ American Geophysical Union 1989