Lever the power out, and the ratio of output to input force is given by the ratio of the distances from the fulcrum to the points of application of these forces. This is known as the "law of the lever." The mechanical advantage of a lever can be determined by considering the balance of moments or torque, "T", about the fulcrum. where F is the input force to the lever and F is the output force. The distances "a" and "b" are the perpendicular distances between the forces and the fulcrum. Since the moments of torque must be balanced, formula_3 .
Darcy Lever constructed with a timber frame with plaster fill and a grey slate roof in the Tudor style. It was located on the high ground that slopes down to Blackshaw Brook, which flowed past the south side of the house near the junction with the River Croal. The hall was demolished in 1951. The growth of the textile industry around Darcy Lever was assisted by the availability of coal. By 1896 John Fletcher owned coal mines at Ladyshore, Little Lever; The Earl of Bradford had a coal mine at Great Lever and the Darcy Lever Coal Company and others had mines