Differential pulley the system becomes a simple "gun tackle" with a mechanical advantage of 2. The same principle is used in a differential windlass, where the connected pulleys are replaced by winches. In the above graphic, the four segments of the chain are labelled W, X, Y and Z. The magnitudes of their corresponding forces are "F", "F", "F" and "F", respectively. Assuming that the chain is massless, "F" = 0 because segment X is not supporting any weight. Taking the system at equilibrium, "F" and "F" are equal — if they were not, the lower pulley would freely turn until they
Hook Estate and Kennels and grassland (c.1931), purchased by the Greyhound Racing Association (GRA), soon after the first oval track racing arrived in the United Kingdom. The kennels were located on what was formerly Hook Farm, south of Hook Wood. The mansion 'Hook House' or 'The Hook' served as a base for some of the senior staff including the kennel manager and veterinary surgeon and the Hook Cottages and newly built Hook villas were divided among the trainers and their families attached to the GRA's racetracks. The kennels opened with 150 employees and there was a separate kennel block for each of the original