It has been observed that the pattern of particle impact breakage in two-dimensional systems is a result of two mechanisms. "Mechanism I" accounts for the breakage induced by the stresses that appear in unbroken particles, "Mechanism II" breakage is due to the buckling of the Mechanism I fragments. The purpose of this paper is to try and understand the parameters that govern the magnitude of the breakage induced by the various mechanisms-in particular, to understand the specific effects of impact velocity on the size distribution. To that end, a dimensionless parameter that governs the magnitude of the breakage induced by Mechanism I in both two and three dimensions is developed. The two-dimensional analysis demonstrates a velocity dependence for the Mechanism I breakage that accounts for the observed velocity effect on the generated size distributions. However, the three-dimensional analysis demonstrates no such velocity effect. Both findings are supported by simulation results.