The speedy steel plate
Stories from Physics for 11-14 14-16
One of the fastest moving man-made objects ever detected was a manhole cover. As a result of the Pascal-B nuclear test in Nevada in 1957, a 900 kg steel plate cap was blown off the top of a test shaft at a speed of more than 66 km/s. The plate was never found, and the experiment’s designer, Dr Brownlee, believes that although the plate may have exceeded Earth’s escape velocity, it is likely to have been vaporised by compression heating in the atmosphere. The calculated velocity is an estimate as the high-speed camera footage of the incident captured the cap in just one frame.