Bicycle pump

A bicycle pump is a type of positive-displacement pump specifically designed for inflating bicycle tires. It has a connection or adapter for use with one or both of the two most common types of valves used on bicycles, Schrader or Presta. A third type of valve called the Woods valve exists, but tubes with these valves can be filled using a Presta pump.

Several basic types are available:

In its most basic form, a bicycle pump functions via a hand-operated piston. During the up-stroke, this piston draws air through a one-way valve into the pump from the outside. During the down-stroke, the piston then displaces the air from the pump into the bicycle tire. Most floor pumps, also commonly called track pumps, have a built in pressure gauge to indicate tire pressure.

Electrically-operated pumps intended to inflate car tires (as available in most service stations) can in principle be used to inflate a bicycle tire if the right type of connection is available. Some such pumps are designed to cut off before a suitable pressure (much higher for a bicycle than a car tire), and will much underinflate the tire. Others may not cut off, but deliver a high rate of flow to fill the larger car tire, with a risk of overinflating and bursting a bicycle tire unless it is stopped with split-second timing.

Part number

A part number (often abbreviated PN, P/N, part no., or part #) is an identifier of a particular part design used in a particular industry. Its purpose is to simplify reference to that part. A part number unambiguously identifies a part design within a single corporation, and sometimes across several corporations.

For example, when specifying a screw, it is easier to refer to "HSC0424PP" than saying "Hardware, screw, machine, 4-40, 3/4" long, panhead, Phillips". In this example, "HSC0424PP" is the part number, and it may be prefixed in database fields as "PN HSC0424PP" or "P/N HSC0424PP".

The part design versus instantiations of it

As a part number is an identifier of a part design (independent of its instantiations), a serial number is a unique identifier of a particular instantiation of that part design. In other words, a part number identifies any particular (physical) part as being made to that one unique design; a serial number, when used, identifies a particular (physical) part (one physical instance), as differentiated from the next unit that was stamped, machined, or extruded right after it. This distinction is not always clear, as natural language blurs it by typically referring to both part designs, and particular instantiations of those designs, by the same word, "part(s)". Thus if you buy a muffler of P/N 12345 today, and another muffler of P/N 12345 next Tuesday, you have bought "two copies of the same part", or "two parts", depending on the sense implied.

Dude Perfect

Dude Perfect is a sports entertainment group who got their start on YouTube. Most known for their trick shots, they are also involved in comedy with their "Stereotypes" series, in which they poke fun at common stereotypes, mostly in the sports world. The group consists of the twins Coby and Cory Cotton, Garrett Hilbert, Cody Jones, and Tyler Toney who are all former high school basketball players and college roommates at Texas A&M University.

The group commented that their shots typically relied more on American football skills than basketball.

History

The group was betting on sandwiches via basketball shots in their backyard, which were eventually recorded on camera, and a video of trick shots at Toney's ranch was eventually released on YouTube. Within a week, the video received 100,000 views. When asked about the name, Toney stated,

Afterwards, a trick shot video from the Christian summer camp Sky Ranch was released, which, as of June 2015, has over 13.9 million views. For every 100,000 views the video received, Dude Perfect pledged to sponsor a child from Compassion International. Afterwards, ESPN's E:60 contacted the group for a segment, and on the third floor of Texas A&M's Kyle Field, Toney converted a shot, which traveled 3.9 seconds, which was a world record at the time. The shot prompted television appearances on ESPN's First Take, Pardon the Interruption, Around the Horn and SportsNation. Eventually, Dude Perfect introduced the Panda mascot, who "developed a cult following at A&M basketball games" when taunting players of the opposing team.

Hot rod

Hot rods are typically old, classic American cars with large engines modified for linear speed. The origin of the term "hot rod" is unclear. A possible origin includes replacement of the camshaft with a new ("hotter") version, sometimes known as a hot stick or hot rod. Roadsters were the cars of choice because they were light, easy to modify, and inexpensive. The term became commonplace in the 1930s or 1940s as the name of a car that had been "hopped up" by modifying the engine for higher performance. A term common in the early days was "gow job". This has fallen into disuse except with historians.

The term has broadened to apply to other items that are modified for a particular purpose, such as "hot-rodded amplifier".

History

Late 1930s–1950s

The term seems first to have appeared in the late 1930s in southern California, where people raced modified cars on dry lake beds northeast of Los Angeles under the rules of the Southern California Timing Association (SCTA), among other groups. The activity increased in popularity after World War II, particularly in California, because many returning soldiers received technical training in the service. Many cars were prepared by bootleggers in response to Prohibition to enable them to avoid revenue agents ("Revenooers"); some police vehicles were also modified in response.

Number

A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, and so forth. A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, the term number may refer to a symbol, a word, or a mathematical abstraction.

In mathematics, the notion of number has been extended over the centuries to include 0, negative numbers, rational numbers such as and , real numbers such as and , complex numbers, which extend the real numbers by including , and sometimes additional objects. Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Their study or usage is called arithmetic. The same term may also refer to number theory, the study of the properties of the natural numbers.