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"
William Lever, 1st Viscount Leverhulme about advertising, "I know half my advertising isn't working, I just don't know which half." William Lever, 1st Viscount Leverhulme William Hesketh Lever, 1st Viscount Leverhulme (; 19 September 1851 – 7 May 1925) was an English industrialist, philanthropist, and politician. Having been educated at a small private school until the age of nine, then at church schools until he was fifteen; a somewhat privileged education for that time, he started work at his father's wholesale grocery business in Bolton. Following an apprenticeship and a series of appointments in the family business, which he successfully expanded, he began manufacturing Sunlight