Dodatkowe przykłady dopasowywane są do haseł w zautomatyzowany sposób - nie gwarantujemy ich poprawności.
Seesaws and crowbars are examples of first class levers.
It does so by keeping the shoe open and by providing a smooth surface for the foot and the heel to move, without crushing the shoe's counter (the vertical portion of the shoe that wraps around the back of the foot), in this way acting as a first class lever.