Search results
Results From The WOW.Com Content Network
A microsecond is to one second, as one second is to approximately 11.57 days. A microsecond is equal to 1000 nanoseconds or 1 ⁄ 1,000 of a millisecond. Because the next SI prefix is 1000 times larger, measurements of 10 −5 and 10 −4 seconds are typically expressed as tens or hundreds of microseconds.
One barn is equal to 1.0 × 10 −28 m 2. The name derives from the folk expressions "As big as a barn," and "Couldn't hit the broad side of a barn", used by particle accelerator physicists to refer to the probability of achieving a collision between particles. For nuclear purposes, 1.0 × 10 −28 m 2 is actually rather large. [25]
A millisecond (from milli-and second; symbol: ms) is a unit of time in the International System of Units equal to one thousandth (0.001 or 10 −3 or 1 / 1000) of a second [1] [2] or 1000 microseconds. A millisecond is to one second, as one second is to approximately 16.67 minutes.
Its SI unit is the reciprocal seconds (s −1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). [ 1 ] [ a ] [ b ] Rotational frequency can be obtained dividing angular frequency , ω, by a full turn (2 π radians ): ν =ω/(2π rad).
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. It depends strongly on temperature as well as the medium through which a sound wave is propagating.
The inverse second or reciprocal second (s −1), also called per second, is a unit defined as the multiplicative inverse of the second (a unit of time). It is applicable for physical quantities of dimension reciprocal time , such as frequency and strain rate .
The unambiguous velocity of an L-Band radar using a PRF of 10 kHz would be 1,500 m/s (3,300 mile/hour) (10,000 x C / (2 x 10^9)). True velocity can be found for objects moving under 45,000 m/s if the band pass filter admits the signal (1,500/0.033). Medium PRF has unique radar scalloping issues that require redundant detection schemes.
To relate radar timing to distances traveled by radar energy, the speed is used to calculate it. With speed of radar waves at approximately the speed of light in vacuum or 299,792,458 metres per second (300 m/μs; 984 ft/μs) and nautical mile at 1,852 metres (6,076 ft), the delay per nautical mile until the wave return is calculated as: