▁defined ▁relative ▁to ▁that ▁for ▁a ▁particular ▁state . ▁This ▁reference ▁state ▁is ▁not ▁always ▁a ▁real ▁state ; ▁it ▁may ▁also ▁be ▁a ▁limit , ▁such ▁as ▁with ▁the ▁distances ▁between ▁all ▁bodies ▁t ending ▁to ▁infinity , ▁provided ▁that ▁the ▁energy ▁involved ▁in ▁t ending ▁to ▁that ▁limit ▁is ▁finite , ▁such ▁as ▁in ▁the ▁case ▁of ▁inverse - square ▁law ▁forces . ▁Any ▁arbitrary ▁reference ▁state ▁could ▁be ▁used ; ▁therefore ▁it ▁can ▁be ▁chosen ▁based ▁on ▁convenience . ▁ ▁Typ ically ▁the ▁potential ▁energy ▁of ▁a ▁system ▁depends ▁on ▁the ▁relative ▁positions ▁of ▁its ▁components ▁only , ▁so ▁the ▁reference ▁state ▁can ▁also ▁be ▁expressed ▁in ▁terms ▁of ▁relative ▁positions . ▁ ▁Gra v it ational ▁potential ▁energy ▁ ▁Gra v it ational ▁energy ▁is ▁the ▁potential ▁energy ▁associated ▁with ▁gravit ational ▁force , ▁as ▁work ▁is ▁required ▁to ▁elev ate ▁objects ▁against ▁Earth ' s ▁gravity . ▁The ▁potential ▁energy ▁due ▁to ▁elev ated ▁positions ▁is ▁called ▁gravit ational ▁potential ▁energy , ▁and ▁is ▁ev iden ced ▁by ▁water ▁in ▁an ▁elev ated ▁res er voir ▁or ▁kept ▁behind ▁a ▁dam . ▁If ▁an ▁object ▁falls ▁from ▁one ▁point ▁to ▁another ▁point ▁inside ▁a ▁gravit ational ▁field , ▁the ▁force ▁of ▁gravity ▁will ▁do ▁positive ▁work ▁on ▁the ▁object , ▁and ▁the ▁gravit ational ▁potential ▁energy ▁will ▁decrease ▁by ▁the ▁same ▁amount . ▁ ▁Consider ▁a ▁book ▁placed ▁on ▁top ▁of ▁a ▁table . ▁As ▁the ▁book ▁is ▁raised ▁from ▁the ▁floor ▁to ▁the ▁table , ▁some ▁external