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GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.
A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991–1802 BC) [1] and Mesopotamia in the early 2nd millennium BC. [2]
Triple Award Science, commonly referred to as Triple Science, results in three separate GCSEs in Biology, Chemistry and Physics and provide the broadest coverage of the main three science subjects. The qualifications are offered by the five main awarding bodies in England; AQA , Edexcel , OCR , CIE and Eduqas .
Belt replacement is an obvious solution, and eventually the mandatory one (because no belt lasts forever). Often, though, before the replacement option is executed, retensioning (via pulley centerline adjustment) or dressing (with any of various coatings) may be successful to extend the belt's lifespan and postpone replacement.
April Pulley Sayre (April 11, 1966 — November 6, 2021) was an American children's book author from the 1990s to 2020s. Before becoming an author, Sayre worked at the National Wildlife Federation and National Geographic Society .
An illustration showing how pulleys are used to obtain a mechanical advantage. Using additional pulleys decreases the force required but increases the distance required to raise a load the same amount. In each instance here the mechanical work done is the same, work being the product of force and distance. F Z × s = F L × h 10 cm × 100 N = 10 J
A dumb pulley can lift very large masses a short distance. It consists of two fixed pulleys of unequal radii that are attached to each other and rotate together, a single pulley bearing the load, and an endless rope looped around the pulleys. To avoid slippage, the rope is usually replaced by a chain, and the connected pulleys by sprockets.
The belt problem is a mathematics problem which requires finding the length of a crossed belt that connects two circular pulleys with radius r 1 and r 2 whose centers are separated by a distance P. The solution of the belt problem requires trigonometry and the concepts of the bitangent line, the vertical angle, and congruent angles.