s ▁Category : Arch itect s ▁who ▁committed ▁suic ide ▁Category : Su ic ides ▁by ▁fire arm ▁in ▁Wales ▁Category : 1 9 th - century ▁Wel sh ▁po ets ▁Category : 1 9 th - century ▁Wel sh ▁architect s <0x0A> </s> ▁Rot ational ▁speed ▁( or ▁speed ▁of ▁revolution ) ▁of ▁an ▁object ▁rot ating ▁around ▁an ▁axis ▁is ▁the ▁number ▁of ▁turns ▁of ▁the ▁object ▁divided ▁by ▁time , ▁specified ▁as ▁revolution s ▁per ▁minute ▁( r pm ), ▁cycles ▁per ▁second ▁( c ps ), ▁rad ians ▁per ▁second ▁( rad / s ), ▁etc . ▁ ▁The ▁symbol ▁for ▁rot ational ▁speed ▁is ▁( the ▁Greek ▁lower case ▁letter ▁" omega "). ▁ ▁Tang ential ▁speed ▁v , ▁rot ational ▁speed ▁, ▁and ▁radial ▁distance ▁r , ▁are ▁related ▁by ▁the ▁following ▁equation : ▁ ▁An ▁algebraic ▁re arr ang ement ▁of ▁this ▁equation ▁allows ▁us ▁to ▁solve ▁for ▁rot ational ▁speed : ▁ ▁Thus , ▁the ▁tang ential ▁speed ▁will ▁be ▁directly ▁proportional ▁to ▁r ▁when ▁all ▁parts ▁of ▁a ▁system ▁simultaneously ▁have ▁the ▁same ▁ ω , ▁as ▁for ▁a ▁wheel , ▁disk , ▁or ▁rig id ▁wand . ▁The ▁direct ▁proportional ity ▁of ▁v ▁to ▁r ▁is ▁not ▁valid ▁for ▁the ▁plan ets , ▁because ▁the ▁plan ets ▁have ▁different ▁rot ational ▁spe eds ▁( ω ). ▁ ▁Rot ational ▁speed ▁can ▁measure , ▁for ▁example , ▁how ▁fast ▁a ▁motor ▁is ▁running . ▁Rot ational ▁speed ▁and ▁angular ▁speed ▁are ▁sometimes ▁used ▁as