From [url]
Note; See also https://books.google.com.om/books?id...ghting&f=false page 69 where it is noted that the Sumerians discovered that making the axe head heavier and sharper pushed the foot pound impact up to 77.5 when the critical power needed to crunch through body armour was only 66 foot pounds... thus they had a winner in hand.... which would be a dominant factor for warfare for the next 2000 years.