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EE Fundamental
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Engineering Fundamentals
Fundamental Dimensions
• We need seven fundamental base dimensions to correctly express what we know of the natural world.
• These are length, mass, @me, temperature, electric current, amount of substance, and luminous intensity
Fundamental Dimensions
• Length: – The name of SI base unit is meters. The symbol is m.
– The range of height for most adults is 1.6 to 2.0 m.
Fundamental Dimensions
• Mass – The name of SI base unit is kilograms. The symbol is kg.
– The range of mass for most adults is between 50 and 120 kg.
Fundamental Dimensions
• Time – The name of SI base unit is seconds. The symbol is s.
– The fastest person can run 100 meters in approximately 10 seconds.
Fundamental Dimensions
• Thermodynamic temperature – The name of SI base unit is Kelvins. The symbol is K.
– A comfortable room temperature is around 300 K.
Fundamental Dimensions
• Electric Current – The name of SI base unit is Amperes. The symbol is A.
– The current on a 100 W lamp is approximately 0.5 A.
Fundamental Dimensions
• Amount of substance – The name of SI base unit is Moles. The symbol is mol.
– Uranium is 238 mol, carbon 12, hydrogen 1.
Fundamental Dimensions
• Luminous Intensity – The name of SI base unit is Candelas. The symbol is cd.
– A candle has a luminous intensity of approximately 1 candela.
Fundamental Dimensions
• The meter is the length of the path traveled by light in a vacuum during a @me interval of 1/299.792.458 of a second.
Jean-‐Bap@ste-‐Joseph-‐Delambre and Pierre-‐François-‐André Méchain
Fundamental Dimensions
• The kilogram is equal to the mass of the interna@onal prototype of the kilogram.
Fundamental Dimensions
• The second is the dura@on of 9.192.631.770 periods of the radia@on corresponding to the transi@on between the two hyperfine levels of the ground state of the cesium 133 atom.
Fundamental Dimensions
• The ampere is that constant current which if maintained in two straight parallel conductors of infinite length, of negligible cross sec@on, and placed 1 meter apart in a vacuum, would produce between these conductors a force equal to 2 X 10-‐7 newton per meter of length.
Fundamental Dimensions
• The kelvin is a frac@on 1/273,16 of the thermodynamic temperature of the triple point of water.
Fundamental Dimensions
• The mole is the amount of substance of a system that contains as many elementary en@@es as there are atoms in 0,012 kilogram of carbon 12.
Fundamental Dimensions
• The candela is the luminous intensity, in a given direc@on, of a source that emits monochroma@c radia@on of frequency 540 X 1012 hertz and that has a radiant intensity in that direc@on of 1/683 wa^ per steradian.
Fundamental Dimensions
Mul$plica$on factor Prefix SI symbol
1024 yo^a Y
1021 ze^a Z
1018 exa E
1015 peta P
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
101 deka da
Fundamental Dimensions
Mul$plica$on factor Prefix SI Symbol
10-‐1 deci d
10-‐2 cen@ c
10-‐3 milli m
10-‐6 micro µ
10-‐9 nano n
10-‐12 pico p
10-‐15 femto f
10-‐18 a^o a
10-‐21 zepto z
10-‐24 yocto y
Fundamental Dimensions
• Accelera@on, angle, angular accelera@on, angular velocity, area, density, etc. are all derived from these fundamental dimensions.
Symbols Used in Engineering and Science
•
Numerical vs Symbolic Solu@ons
• For problems that require a numeric solu@on, data are given and you are required to find an answer in the form of a number.
• In the symbolic solu@on, the steps and the final answer are presented with variables that could be subs@tuted with data if necessary.
Significant Digits
• Significant digits represent and convey the extent to which recorded or computed data are dependable.
• Represent the numbers as 71 ± 1 kg or 3.35 ± 0.05 m.
• Follow the rules of addi@on/subtrac@on and the rules of mul@plica@on/division of significant digits.
• Otherwise, the output of your calculator/computer is garbage.