si - system international the metric system. how high is the ceiling?
TRANSCRIPT
Metric System
• Began in 1795 - French• Standardized - 1960
– What does this mean?
• Terms to Know– Fundamental / Derived– Quantity / Unit
Fundamental vs Derived
• Fundamental Units– Base Unit which is defined to be Universally Understood and Repeatable
– 7 Fundamental Units
• Derived– A combination of more than 1 fundamental units
– Examples: m/s; s2; kgm / s2
– Often given an equivalent expression: Newton, Watt, Joule
Quantities vs Units
QuantitiesAmount or how much of a specific dimension
Examples: Length, Mass, Volume, Density
UnitsDescribes the size in which a quantity is measured
Examples: meter, foot, inch, mile
second, hour, minute, millenium
7 Fundamental Units / Quantities
• Length - meter• Mass - kilogram• Time - second• Electric Current - Ampere• Luminous Intensity - candela• Temperature - Kelvin• Amount of Substance - mole
Standard Definition - meterOld Definition
1 m is defined as 10-7 of the distance from the North Pole to the Equator along a line through Lyon, France
New Definition (1960)
1 m is defined as 1650763.63 times the wavelength of orange-red light from a Krypton-86 lamp
Newest Definition (1982)
1 m is defined as the distance light travels in a vacuum in 1/2999792458 of a second
Standard Definition - second
Old Definition
1 s is defined as 1/86400 of a mean solar day
New Definition (1960)
1 s is defined as duration of 9192631770 cycles of the radiation from Cesium-133
Standard Definition - kilogram
Old Definition
1 kg is defined as the mass of water at its densest (T= 4°C) which fills a volume of 1.0 liter
New Definition (1960)
1 kg is defined as mass of a cylinder of platinum-iridium alloy kept at the International Bureau of Weights and Measures near Paris
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Systems of Measurement
• mks - Meter, Kilogram, Second• cgs - Centimeter, Gram, Second• fps - Foot, Pound, Second
Note: These units are fundamental in that system.
What does it mean to be fundamental???
Systems of Measurement
System Length Mass Time ForceWorkEnergy
mksmeter
mkilogram
kgsecond
s
cgsfps
Red = Fundamental
Systems of Measurement
System Length Mass Time ForceWorkEnergy
mksmeter
mkilogram
kgsecond
s
kg m / s^2Newton
N
kg m^2/s^2N*mJoule
Jcgsfps
Red = Fundamental
Systems of Measurement
System Length Mass Time ForceWorkEnergy
mksmeter
mkilogram
kgsecond
s
kg m / s^2Newton
N
kg m^2/s^2N*mJoule
J
cgscentimeter
cmgram
gsecond
sg cm / s^2
dynedyne*cm
erg
fps
Red = Fundamental
Systems of Measurement
System Length Mass Time ForceWorkEnergy
mksmeter
mkilogram
kgsecond
s
kg m / s^2Newton
N
kg m^2/s^2N*mJoule
J
cgscentimeter
cmgram
gsecond
sg cm / s^2
dynedyne*cm
erg
fpsfootft
slugsecond
s
poundlbp
foot poundft lb
Red = Fundamental