Past exam of the mathematics course of the University of Cambridge / 2025 / iii / Paper 316 / 1 / vii / Solution

A size-independent $Q_D^{\ast }$ gives the steady Dohnanyi collisional cascade exponent $\alpha =7/2$. The preceding results becomeThus, under these idealized prescriptions, cratering collisions remove target mass about three times faster than catastrophic collisions. The conclusion concerns mass removed from targets; both processes contribute fragments to the collisional cascade.