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To help compare different orders of magnitude, the following list describes various speed levels between approximately 2.2 × 10 −18 m/s and 3.0 × 10 8 m/s (the speed of light). Values in bold are exact.
Miles per hour (mph, m.p.h., MPH, or mi/h) is a British imperial and United States customary unit of speed expressing the number of miles travelled in one hour. It is used in the United Kingdom , the United States , and a number of smaller countries, most of which are UK or US territories, or have close historical ties with the UK or US.
In radar-related subjects and in JTIDS, a data mile is a unit of distance equal to 6,000 feet (1,829 metres; 0.9875 nautical miles; 1.136 miles). An international mile is 0.88 data mile. The speed of light is 299,792,458 metres per second (983,571,056 ft/s), or about one foot per nanosecond .
The base units are defined in terms of the defining constants. For example, the kilogram is defined by taking the Planck constant h to be 6.626 070 15 × 10 −34 J⋅s, giving the expression in terms of the defining constants [1]: 131 1 kg = (299 792 458) 2 / (6.626 070 15 × 10 −34)(9 192 631 770) h Δν Cs / c 2 .
The original Naismith's rule from 1892 says that one should allow one hour per three miles on the map and an additional hour per 2000 feet of ascent. [1] [4] It is included in the last sentence of his report from a trip. [1] [8] Today it is formulated in many ways. Naismith's 1 h / 3 mi + 1 h / 2000 ft can be replaced by:
However, more recent data show that Germany ranks in the lower middle field in a Europe-wide comparison regarding the number of fatalities per billion vehicle kilometers traveled on motorways. [169] ETSC considers that those data are not comparable, because estimations of the number of kilometers traveled are not estimated the same way in ...
It translates to an average speed of 15 miles per hour (24 km/h). [1] It is a standard of professional middle-distance runners in several cultures. The first four-minute mile is usually attributed to the English athlete Roger Bannister, who ran it in 1954 at age 25 in 3:59.4. [2] The mile record has since been lowered by 16.27 seconds.
The fastest unmanned (but capable of carrying up to 8-10 people) spaceplane ever built [citation needed], weighing 100 tons or more. Flying between any two airports allow a large number of combinations , so setting a speed record ("speed over a recognised course") is fairly easy with an ordinary aircraft , although there are many administrative ...