There are three classes of levers, depending on the relative positions of the effort is applied, load, and fulcrum. 1  First-class levers have the fulcrum located between the load and the effort (LFE). If the two arms of the lever are of equal length, the effort must be equal to the load.
1 Ebro: From the 120 Foot level of the new cell tower, This is Ebro.
Rating Newest Oldest. Best Answer: el libro is the definite article, un libro is the indefinite article. libro is masculine (-o ending), so we have to use the masuculine definite article: el. definite articles in spanish: el, la, los, las. indefinite articles in spanish: