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Mansa Musa was the ruler of the Mali Empire in West Africa. Details recorded here should be sourced; unknown information is left blank.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
| inverse second | |
|---|---|
| Unit system | SI |
| Unit of | frequency |
| Symbol | s−1 |
| Conversions | |
| 1 s−1 in ... | ... is equal to ... |
| SI units | 1 Hz |
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.
It is dimensionally equivalent to:
However, the special names and symbols above for s−1 are recommend to be used in their domains of application, for clarity, as they are used for different kinds of quantity.[a][b]
The inverse minute or reciprocal minute (min−1), also called per minute, is 60−1 s−1, as 1 min = 60 s; it is used in quantities of type "counts per minute", such as:
Inverse square second (s−2) is involved in the units of linear acceleration, angular acceleration, and rotational acceleration.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
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. It is dimensionally equivalent to: hertz (Hz), historically known as cycles per second – the SI unit for frequency and rotational frequency becquerel (Bq) – the SI unit for the rate of occurrence of aperiodic or stochastic radionuclide events baud (Bd) – the unit for symbol rate over a communication link bit per second (bit/s) – the unit of bit rate radian per second (rad⋅s−1) - the SI unit for angular frequency and angular velocity However, the special names and symbols above for s−1 are recommend to be used in their domains of application, for clarity, as they are used for different kinds of quantity. The inverse minute or reciprocal minute (min−1), also called per minute, is 60−1 s−1, as 1 min = 60 s; it is used in quantities of type "counts per minute", such as: Actions per minute Beats per minute Counts per minute Revolutions per minute (rpm) Words per minute Inverse square second (s−2) is involved in the units of linear acceleration, angular acceleration, and rotational acceleration.
NIST Time & Frequency Service (callsign WWVB) is a longwave time signal radio station near Fort Collins, Colorado, and is operated by the United States Government via the National Institute of Standards and Technology (NIST). Most radio-controlled clocks in North America use WWVB's transmissions to set the correct time. The normal signal transmitted from WWVB is 70 kW ERP and uses a 60 kHz carrier wave yielding a frequency uncertainty of less than 1 part in 1012. The time code signal is derived from a set of atomic clocks located at the site, and transmitted using the IRIG "H" format and modulated onto the carrier wave using pulse-width modulation and amplitude-shift keying at one bit per second. A single complete frame of time code begins at the start of each minute, lasts one minute, and conveys the year, day of year, hour, minute, and other information as of the beginning of the minute. WWVB is co-located with WWV, a time signal station that broadcasts in both voice and time code on multiple shortwave radio frequencies. WWVB is not an acronym or abbreviation but a call sign for the radio station. While most time signals encode the local time of the broadcasting nation, the United States spans multiple time zones, so WWVB broadcasts the time in Coordinated Universal Time (UTC). Radio-controlled clocks can then apply time zone and daylight saving time offsets as needed to display local time. The time used in the broadcast is set by the NIST Time Scale, known as UTC(NIST). This time scale is the calculated average time of an ensemble of master clocks, themselves calibrated by the NIST-F1 and NIST-F2 cesium fountain atomic clocks. In 2011, NIST estimated the number of radio clocks and wristwatches equipped with a WWVB receiver at over 50 million.
In telecommunications and computing, bit rate (bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed as bits per second (symbol: bit/s), often with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used: 1 Mbps is 1 Mbit/s, that is, one million bits per second. The bit rate is different from the transfer rate, measured in transfers per second, when the channel is parallel and thus transfers multiple bits per transfer. In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s (1 byte = 8 bits). However if stop bits, start bits, and parity bits need to be factored in, a higher number of bits per second will be required to achieve a throughput of the same number of bytes.
An order of magnitude is generally a factor of ten. A quantity growing by four orders of magnitude implies it has grown by a factor of 10000 or 104. However, because computers are binary, orders of magnitude are sometimes given as powers of two. This article presents a list of multiples, sorted by orders of magnitude, for bit rates measured in bits per second. Since some bit rates may measured in other quantities of data or time (like MB/s), information to assist with converting to and from these formats is provided. This article assumes the following: A group of 8 bits (8 bit) constitutes one byte (1 B). The byte is the most common unit of measurement of information (megabyte, mebibyte, gigabyte, gibibyte, etc.). The decimal SI prefixes kilo, mega etc., are powers of 10. The power of two equivalents are the binary prefixes kibi, mebi, etc. Accordingly: 1 kB (kilobyte) = 1000 bytes = 8000 bits 1 KiB (kibibyte) = 210 bytes = 1024 bytes = 8192 bits 1 kbit (kilobit) = 125 bytes = 1000 bits 1 Kibit (kibibit) = 210 bits = 1024 bits = 128 bytes
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Shirley Chisholm, elected in 1968.
