In mechanics of materials, the bending stress of a beam in bending can be determined by the equation =Myl where expressed in terms of Sl base units M is the bending moment in Newton-meters (N-m), y is the distance from the neutral axis in meters (m), and /is the moment of inertia in meters to the fourth power (m4). The bending stress o has the same units as those of: a) pressure b) density c) force d) spring constant