In.contrast.with.bearings,.friction.is.a.useful.and.essential.agent.in.belts,.clutches,.and.and.heat.dissipation,.and.so.on..The.foregoing.devices.are.thus.effectively.analyzed.and.surface.forms.affecting.the.equations.more.than.the.functions.of.the.elements..Also,.in.belt.(chain).drives.as.well..Hence,.only.a.few.different.analyses.are.required,.with.