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The first equation shows that, after one second, an object will have fallen a distance of 1/2 × 9.8 × 1 2 = 4.9 m. After two seconds it will have fallen 1/2 × 9.8 × 2 2 = 19.6 m; and so on. The next-to-last equation becomes grossly inaccurate at great distances. If an object fell 10 000 m to Earth, then the results of both equations differ ...
A minute of arc is π 10 800 of a radian . A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol ″, [ 2] is 1 60 of an arcminute, 1 3600 of a degree, [ 1] 1 1 296 000 of a turn, and π 648 000 (about 1 206 264.8) of a radian. These units originated in Babylonian astronomy as ...
Angular diameter: the angle subtended by an object. The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is the angular aperture (of a lens ).
Clock angle problems relate two different measurements: angles and time. The angle is typically measured in degrees from the mark of number 12 clockwise. The time is usually based on a 12-hour clock . A method to solve such problems is to consider the rate of change of the angle in degrees per minute. The hour hand of a normal 12-hour analogue ...
Aircraft maneuvering is referenced to a standard rate turn, [ 1] also known as a rate one turn ( ROT ). A standard rate turn is defined as a 3° per second turn, which completes a 360° turn in 2 minutes. This is known as a 2-minute turn, or rate one (180°/min). Fast airplanes, or aircraft on certain precision approaches, use a half standard ...
Speed of sound. The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn ), or 1 km in 2.91 s or one mile in 4.69 s.
One can also use the 1 in 60 rule to approximate distance from a VOR, by flying 90 degrees to a radial and timing how long it takes to fly 10 degrees (the limit of the course deviation indicator). The time in seconds divided by 10 is roughly equal to the time in minutes from the station, at the current ground speed .
The grade (US) or gradient (UK) (also called stepth, slope, incline, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt ...