Lever force F at a point "A" located by the coordinate vector r on the bar. The lever then exerts an output force F at the point "B" located by r. The rotation of the lever about the fulcrum "P" is defined by the rotation angle "θ" in radians. Let the coordinate vector of the point "P" that defines the fulcrum be r, and introduce the lengths which are the distances from the fulcrum to the input point "A" and to the output point "B", respectively. Now introduce the unit vectors e and e from the fulcrum to the point "A"
Hayley Lever with arthritis in his right hand, which prevented him from further travel and forced him to concentrate on still-life subjects instead. As his arthritis advanced, he taught himself to paint with his left hand. However, following the death of his wife Aida in 1949, Lever was confined to his home, where he continued to paint from 1953 until his death. Hayley Lever died on 6 December 1958 at his home in Mount Vernon, New York. News of his death surprised some: Lever had all but disappeared from public view over two decades earlier, despite once having been enormously popular and