2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/138907I study the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. I derive a relation between the (average) interfacial separation $u$ and the applied normal squeezing pressure $p$. I show that for non-adhesive inte raction and small applied pressure, p is proportional to exp (-u/u_0), in good agreement with recent experimental observation.4 pages, 3 figuresSoft Condensed Mattertext