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Bài giảng Động học chất điểm - Bài: Đơn vị độ dài

Bài giảng cung cấp cho người học các kiến thức: Đơn vị độ dài, hệ thống đo lường, đơn vị cũ,. Hi vọng đây sẽ là một tài liệu hữu ích dành cho các bạn sinh viên đang theo học môn dùng làm tài liệu học tập và nghiên cứu. chi tiết nội dung tài liệu. | Units of length Which units are used to measure length ? Do you know any history of measurent ? Some old units of length Cubit was used most early to measure length last 3000 years. Cubit : the length of the arm, from the elbow to the tip of the middle finger. cubit Foot : To Greek, foot : the width of 16 fingers. To Romas, 1 foot = 12 inches Measuring feet Yard : the distance from the tip of the nose to the thumb of King Henry I Yard : the arcumference of a person’s waist. Henry I The yardstick (Henry I, thumb to nose). Some different units: fermi (fm), anxtrom, micron, RE ( radius of Earth) AU ( astronomical unit) LY ( light year) Arrange from smallest to great : inches feet yards miles Definition of metre 1799, The meter standard, a platinum The bar, is officially presented in Pari 1889, the length of that platinum bar with no longer reference to the Earth meridian. Length measurement 1960, equal 1650763.73 wavelengths of the red-orange radiation of Kripton atom. 1983, metre is the distance travelled in vacuum by electromagnetic wave in 1 / 299792458 of a second. 1960, equal 1650763.73 wavelengths of the red-orange radiation of Kripton atom 1989, metre is the distance travelled in vacuum by electromagnetic wave in 1/299792458 of a second. And then, metre was used as mainly unit of length. Metric system Metre, inclue centimetre, kilometre Non – SI unit : fermi ( fm) = 1 femtometre angxtrom = 100 picometres micron = 1 micrometre Swedish mile = 1000 metres Imperical unit inch = 25.4 mm foot = 12 inches = 0.3048 m yard = 3 feet = 0.9144m mile = 5282 feet = 1609.344m Astronomical units : Earth radius ( RE ) : ~6370 kilometres astronomical unit (AU) : ~ 149 gigametres light year : ~ 9.46 petametres . | Units of length Which units are used to measure length ? Do you know any history of measurent ? Some old units of length Cubit was used most early to measure length last 3000 years. Cubit : the length of the arm, from the elbow to the tip of the middle finger. cubit Foot : To Greek, foot : the width of 16 fingers. To Romas, 1 foot = 12 inches Measuring feet Yard : the distance from the tip of the nose to the thumb of King Henry I Yard : the arcumference of a person’s waist. Henry I The yardstick (Henry I, thumb to nose). Some different units: fermi (fm), anxtrom, micron, RE ( radius of Earth) AU ( astronomical unit) LY ( light year) Arrange from smallest to great : inches feet yards miles Definition of metre 1799, The meter standard, a platinum The bar, is officially presented in Pari 1889, the length of that platinum bar with no longer reference to the Earth meridian. Length measurement 1960, equal 1650763.73 wavelengths of the red-orange radiation of Kripton atom. 1983, metre is .