Speed of a KnotDate: 06/10/99 at 13:26:45 From: mo Subject: Speed of a knot How fast is a knot? Date: 06/10/99 at 15:49:59 From: Doctor Rick Subject: Re: Speed of a knot Hi, Mo. A knot is one nautical mile per hour. 1 nautical mile = 6076.115 feet = 1.150779 statute miles = 1.852 km (exactly) so 1 knot = 1.15 mph = 1.852 km/h. The length of a nautical mile is defined as the length of 1 minute (1/60 degree) of latitude; being not that far from a statute mile (5280 feet), it was given the same name. But the nautical mile is the natural unit of distance to use at sea, where one's position was found in terms of latitude and longitude by celestial navigation with the sextant. Therefore the knot was the natural unit for measuring speed at sea. The name of the knot comes from the means of measuring a ship's speed. Sailors would heave a log into the water attached to a rope. The rope had knots in it, and a sailor would count the knots that passed through his hands in a certain amount of time. The book in which speed (measured by heaving the log) and position were recorded was called the ship's log, so there are at least two terms that came from this practice. - Doctor Rick, The Math Forum http://mathforum.org/dr.math/ |
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