The DC motor was the mainstay of electric traction drives on both electric and diesel-electric locomotives, street-cars/trams and diesel electric drilling rigs for many years. The introduction of DC motors and an electrical grid system to run machinery starting in the 1870s started a new second Industrial Revolution.
One acre is 43,560 sq ft. One half acre is 21,780 sq ft. However, that doesn't help most people much when trying to picture how large a lot is. Half acre lot is roughly:
Best Answer: An acre is approximately 211 ft x 211 ft it is a square unit of measure. One acre comprises 4,840 square yards, 43,560 square feet. A mile is 5,280 ft long it is a linear unit of measure. If you want to know measurements of an acre in square miles it is 211/5280 x 211/5280 square miles. An acre is much much smaller than a square mile.