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In fluid dynamics, dynamic pressure (denoted by q or Q and sometimes called velocity pressure) is the quantity defined by: [1] = where (in SI units): q is the dynamic pressure in pascals (i.e., N/m 2, ρ (Greek letter rho) is the fluid mass density (e.g. in kg/m 3), and; u is the flow speed in m/s.
As the velocity of the runner increases, inertia and air resistance effects become the limiting factors on the sprinter's top speed. It was previously believed that there was an intramuscular viscous force that increased proportionally to the velocity of muscle contraction that opposed the contractile force; this theory has since been disproved ...
The world record in the 100-meter dash in 1924 was 10.4 seconds, while in 1948, (the first use of starting blocks) was 10.2 seconds, and was 10.1 seconds in 1956. The constant drive for faster athletes with better technology has brought man from 10.4 seconds to 9.58 seconds in less than 100 years.
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
The concept of pressure is central to the study of both fluid statics and fluid dynamics. A pressure can be identified for every point in a body of fluid, regardless of whether the fluid is in motion or not. Pressure can be measured using an aneroid, Bourdon tube, mercury column, or various other methods.
As an exception, according to rule 36.2, specific event organizers may choose to ignore wind velocity readings exclusively for their specific event records (e.g. a performance in a 100 m race at a meeting with a wind reading of +2.4 m/s may be considered that specific meeting record, but will not be considered as a world record). [1]
Adolph Plummer (January 3, 1938 – November 30, 2015) [2] [3] was an American track and field athlete. He is best known for breaking the world record in the 440 yard dash in 1963, the last runner to hold the 400 m record with a time recorded for the longer 440 yards.
In terms of judging a person's speed, the best method of timing is through lasers which start and stop the times when passed through. A laser start (from a stationary position) is more accurate for measuring pure speed as it does not register a runner's reaction time, however, this method of timing a 40-yard dash can affect the accuracy by as much as 0.5 seconds with the manual stopwatch method.