Units and Dimensions

موضوع: Units and Dimensions الثلاثاء أكتوبر 06, 2009 12:52 pm

Units, Dimensions, Conversions

Units, Dimensions, Conversions

بعض الوحدات والابعاد الهامة
التى يحتاج اليها كل طلاب هندسة

Units and Dimensions

Table C.1: SI units with c.g.s. and British system equivalents

Quantity	Dimensions	SI	c.g.s.	British
*Basic*
Length	L	1 m	= 10² cm	= 3.281 ft
Mass	M	1 kg	= 10³ g	= 2.205 lb
Time	T	1 s	= 1 s	= 2.778 x^-4 h 10
Temperature		1 K	= 1 K	= 1.8 ^oF
*Derived*
Area	L²	1 m²	= 10⁴cm²	= 10.76 ft²
Volume	L³	1 m³	= 10⁶cm³	= 35.31 ft³
Density	M L^-3	1 kg m^-3	= 10^-3 g cm^-3	= 6.243 x^-2 lb ft^-3 10
Velocity	L T^-1	1 m s^-1	= 10² cm s^-1	= 3.281 ft s^-1
Acceleration	L T^-2	1 m s^-2	= 10² cm s^-2	= 3.281 ft s^-2
Force	ML T^-2	1 kg m s^-2	= 10⁵ g cm s^-2	= 0.225 lb f
		= 1 N (Newton)	= 10⁵ dynes	(lb force)
Pressure	M L^-1 T^-2	1 kg m^-1s^-2	= 10 g cm^-1 s^-2	= 0.021 lb f ft^-2
		= 1 Pa (Pascal)	= 10^-2 hPa (or mb)
Work, energy	ML² T^-2	1 kg m²s^-2	= 10⁷ g cm² s^-2	= 0.738 ft lb f
		= 1 J (Joule)	= 10⁷ ergs
Power	ML² T^-3	1 kg m²s^-3	= 10⁷ g cm² s^-3	= 0.738 ft lb f s^-1
		= 1 W (Watt)	= 10⁷s^-1 ergs
Heat, energy	Q (= ML²T^-2)	1 J	= 0.2388 cal	= 9.487 x10^-4 BTU
Heat flux	QT^-1	1 W	= 0.2388 cal s^-1	= 3.412 BTU h^-1
Heat flux density	QL^-2 T^-1	1 W m^-2	= 2.388 x10^-5	= 0.317
			cal cm^-2s^-1	BTU ft^-2h^-1
Latent heat	QM^-1	1 J kg^-1	= 2.388 x10^-4	4.29 x10^-4
			cal g^-1	BTU lb^-1
Specific heat	QM^-1 ^-1	1 J kg^-1K^-1	= 2.388 x10^-4	= 2.388 x10^-4
			cal g^-1K^-1	BTU lb^-1^oF^-1
Thermal	QL^-1 ^-1T^-1	1 W m^-1K^-1	= 2.388 x10^-3	= 0.578
conductivity			cal cm^-1s^-1 K^-1	BTU ft^-1h^-1 ^oF^-1
Thermal	L² T^-1	1 m² s^-1	= 10⁴cm² s^-1	= 10.8 ft²s^-1
diffusivity

التكملة ..ونا خذ نبذة عن بعض الكميات الفيزيا ئية
Units, Dimensions, Conversions
Useful Metric to English Conversions

Length: 1 kilometer (km) = 1000 meters (m) = 0.6214 miles (mi) = 3281 feet (ft)

1 meter = 100 centimeters (cm) = 1.0936 yards (yd) = 3.281 feet = 39.37 inches (in)

1 centimeter = 10 millimeters (mm) = 0.3937 inches

1 micron (m)= 10^-6 meters = 10^-4 centimeters = 3.937
x 10^-5 inches

Area: 1 square kilometer (1 km²) = 10⁶ sq. meters (m²) = 0.3861 sq. miles (mi²) = 247.1 acres

1 m² = 10⁴ sq. centimeters (cm²) = 1.196 sq. yards = 10.764 sq. feet = 1550.0 sq. inches

Volume: 1 cubic kilometer = 10⁹ cubic meters (m³) = 0.2399 cubic miles

1 cubic meter = 10⁶ cubic centimeters = 1.308 cubic yards = 35.31 cubic feet = 61024 cubic inches

1 litre (1) = 1000 cm³ = 10^-3 cubic meters = 0.264 US gallons (US gal) = 61.024 in³

Mass: 1 metric ton (tonne) = 1000 kilograms = 2204.6 avoirdupois pounds (means pound of mass not force)

1 kilogram (kg) = 1000 grams (g) = 2.2046 avoirdupois pounds

Time: 1 day = 86400 seconds (s)

1 year (yr) =
3.156 x 10⁷ seconds

Velocity / 1 meter/second (same as m/s, read meter per second) = 3.281 feet/second = 2.24 miles/hour

Speed: 1 m/s = 3.6 kilometers /hour = 2.237 miles/hour

1 kilometer/hour = 0.62 miles/hour (mi/hr)

1 knot = 1 nautical mile/hour = 1.151 miles/hour = 0.51 m/s = 1.85 km/hr

Force: 1 newton (N) = 1 kilogram meter/(sq. second)

1 newton (N) = 1 kg m^-1 s^-2 = 0.2248 pounds force

Pressure: 1 atmosphere = 1013.2 hectopascals (hPa) = 101.32 kilopascals (kPa)

1 atmosphere = 14.7 pounds/ sq. inch (lb/in²)

1 atmosphere = 760 millimeters of mercury (mm Hg) = 29.92 inches of mercury

10 millibars (hPa) = 1 kilopascal (kPa)

1 Pascal (Pa) = 1 newton /meter² = 0.01 millibars (mb) = 0.01 hectopascals (hPa)

1 millibar (mb) = 1 hectopascal (hPa)

Temperature:

Temperature in ^oC = 5/9(temperature in ^oF - 32)

Temperature in ^oF = 9/5(temperature in ^oC) + 32

Temperature in K = temperature in ^oC + 273.15

Energy: 1 joule (J) = 1 newton meter (N m) = 1 kg m² s^-2 = 0.239 calories = 1 watt sec (W s)

1 calorie (cal)= 4.186 joules (J)

1 langley = 1 calorie /square centimeter

1 kilowatt hour =
3.6 x 10⁶ J

Power: 1 watt (W) = 1 joule / second (J / s) = 14.3353 calories /minute (cal/min)

1 calorie/second = 4.186 joules /second (J/s) = 4.186 watts (W)

1 calorie/minute = 0.06973 watts (W)

1 horsepower