A minute of arc; arcminute; or minute of angle (MOA), is a unit of angular measurement, equal to one sixtieth (1⁄60) of one degree. In turn, a second of arc or arcsecond is one sixtieth (1⁄60) of one minute of arc. These are accepted for use with calculations involving SI units.
However, they are not themselves SI units because they are dimensionless.
1 minute of arc=1⁄(360X60)
Since one degree is defined as one three hundred and sixtieth (1⁄360) of a circle, 1 minute of arc is 1⁄21,600 of the same. By international agreement it is exactly 1,852 metres (approximately 6,076 feet).
The nautical mile (symbol M, NM or nmi) is a unit of length that is about one minute of arc of latitude along any meridian, but is approximately one minute of arc of longitude only at the equator.
That means
The diameter of the earth at the equator is 7926.41 miles (12756.32 kilometers).
Circumferance through equator =12756.32*3.14 = 1,852* 21600
A cargo ship will run at the most efficient speed that allows it to reach its destination at the desired time, and no faster. Fuel is expensive and the ship doesn't make any extra money for arriving early. Most major shipping lines have complex policies in place that dictate the speed requirements. The speed is monitored many times a day and adjusted as necessary to account for currents, weather, and changes to the arrival time. Ships usually travel between 16 and 22 knots.
Cruise ships will adjust their speed to get from port to port in the time alloted. They typically want to arrive at a port early in the morning, before the passengers get up. They are a little bit less concerned about fuel efficiency and will run slightly higher speeds to make the appropriate arrival times.
The latitude and longitude of India is:
20° 0' 0" N / 77° 0' 0" E
If you want to travel through costal area of Kerala (The state has a coast of length 590 km) it will tale average of 16hrs.
Radians are another way of measuring angles instead of degrees. One radian is approximately 57.3°
π (Pi) is 3.14 radians , So 180°=π X 57.3°.
Arc length is the degree ratio of circumference of a circle.
The formula the arc measure is:
 | where: C is the central angle of the arc in degrees R is the radius of the arc π is Pi, approximately 3.142 |
No comments:
Post a Comment