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Leonardo da Vinci is usually credited with conducting the first systematic study of friction in the late 15th century, a subfield now known as tribology that deals with the dynamics of interacting surfaces in relative motion. Da Vinci's notebooks depict how he pulled rows of blocks using weights and pulleys, an approach that is still used in frictional studies today, as well as examining the friction produced in screw threads, wheels, and axles. The authors of this latest paper used an experimental setup similar to da Vinci's.
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For the next few days, Jupiter, Saturn, Venus, Mercury, Neptune and Uranus will all be visible at the same time in the night sky – although binoculars or a telescope will be needed to spot the latter two planets.
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