In engineering, if you do not know what you are doing, you should not be doing it.
Spelling[ edit ] Metre is the standard spelling of the metric unit for length in nearly all English-speaking nations except the United States    and the Philippines,  which use meter.
Other Germanic languages, such as German, Dutch, and the Scandinavian languages  likewise spell the word meter. Measuring devices such as ammeterspeedometer are spelled "-meter" in all variants of English.
History of definition[ edit ] Main article: History of the metre In the English cleric and philosopher John Wilkins proposed in an essay a decimal-based unit of length, the universal measure or standard based on a pendulum with a two-second period.
Christiaan Huygens had observed that length to be 38 Rijnland inches or In Gabriel MoutonBishop of Lyon, also suggested a universal length standard with decimal multiples and divisions, to be based on a one-minute angle of the Earth's meridian arc or as the Earth's circumference was not easy to measure on a pendulum with a two-second period.
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
October Learn how and when to remove this template message Inthe French Academy of Sciences selected the meridional definition over the pendular definition because the force of gravity varies slightly over the surface of the Earth, which affects the period of a pendulum.
To establish a universally accepted foundation for the definition of the metre, more accurate measurements of this meridian were needed.
This portion of the meridian, assumed to be the same length as the Paris meridianwas to serve as the basis for the length of the half meridian connecting the North Pole with the Equator. The problem with this approach is that the exact shape of the Earth is not a simple mathematical shape, such as a sphere or oblate spheroidat the level of precision required for defining a standard of length.
The irregular and particular shape of the Earth smoothed to sea level is represented by a mathematical model called a geoidwhich literally means "Earth-shaped". Despite these issues, in France adopted this definition of the metre as its official unit of length based on provisional results from this expedition.
However, it was later determined that the first prototype metre bar was short by about micrometres because of miscalculation of the flattening of the Earth, making the prototype about 0. Regardless, this length became the French standard and was progressively adopted by other countries in Europe.
This new organisation was to construct and preserve a prototype metre bar, distribute national metric prototypes, and maintain comparisons between them and non-metric measurement standards. Wavelength definition[ edit ] Inthe standard metre was first measured with an interferometer by Albert A. Michelsonthe inventor of the device and an advocate of using some particular wavelength of light as a standard of length.
Byinterferometry was in regular use at the BIPM.
An intended by-product of the 17th CGPM's definition was that it enabled scientists to compare lasers accurately using frequency, resulting in wavelengths with one-fifth the uncertainty involved in the direct comparison of wavelengths, because interferometer errors were eliminated.We have taken our award winning % scale LTV A-7 Corsair II design and made it available as a true turbine ARF!Encompassing all of the scale features from our existing A-7 kit, the ARF will come out of the box ready for your electronics installation.
A Goals Essay connects past, present and future i.e.
your past work- experience (past), your goals, (future), and the need of an MBA from a particular school to achieve your goals (present). In one of the classes I teach at CCA, students were confused by mental models, conceptual models, concept maps, etc.
The table below presents an abbreviated geologic time scale, with times and events germane to this essay. Please refer to a complete geologic time scale when this one seems inadequate. We dig into the details of the new prototype Cannondale aero road bike spotted at the Giro d'Italia. LaRa-OHVD: An Innovative Over-Height Vehicle Detection System to Protect our Bridges to Prosperity Abhishek Singhal, Ph.D. Candidate in Transportation Engineering.
I ended up drawing a taxonomy for models on the whiteboard, and it may help. Information based on data from leslutinsduphoenix.com, leslutinsduphoenix.com, and leslutinsduphoenix.com.
The Mottos Say It All.
jQuery is designed to change the way that you write. May (This essay is derived from a keynote at Xtech.) Startups happen in clusters. There are a lot of them in Silicon Valley and Boston, and few in Chicago or Miami.
We dig into the details of the new prototype Cannondale aero road bike spotted at the Giro d'Italia.