R x I2
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TRANSCAT TECHNICAL REFERENCE
E
I
Conversions
Pressures and Densities
Pressure
Electricity
force
area
=
1 ampere = 1 coulomb per second
1 volt = 1 joule per coulomb
1 column of water 1 foot deep = 62.4 pounds per square foot,
or 0.433 pounds per square inch. 1 column of water 1 centimeter
deep = 1 gram per square centimeter.
Specific gravity (liquid) = number of times a substance is as heavy
as an equal body of water, or specific gravity (liquid) =
weight of liquid
weight of equal volume of water
Density
weight
volume
=
Pressure = depth x density, or force per unit area. An increase in
pressure is transmitted equally through the liquid.
Specific gravity (solid) =
weight of body
weight of equal volume of water
or specific gravity (solid) =
weight of body
loss of weight in water
One cubic yard of air weighs about 2 pounds. Atmospheric pressure
at sea level = about 15 pounds per square inch.
Velocities and Energies
Velocity
distance
time
=
32 feet per second
seconds
weight
x
acceleration of gravity
(velocity)2
radius
=
Ampere = electric current
Volt = potential difference
Ohm = electrical resistance
One volt potential difference will drive 1 ampere through a
resistance of 1 ohm.
The resistance of conductor can be calculated by
the formula:
R = kl (Where l is length, d is diameter, and k is constant)
d2
The combined resistance of conductors connected in parallel is
1
1
1
1
+
+
Rc = R1
R2
R3
1 watt is the power of a current on 1 ampere when the potential
difference is 1 volt.
To compute electric power: P (power in watts) = V (voltage in volts)
x l (current in amperes), or P = V x I.
To compute the heat (H), produced by a current (I),
through a resistance (R), in a time (t), use the equation:
H = I2 x R x t x 0.24 cal/watt-sec.
weight
acceleration of gravity
Index of refraction =
velocity of light in air
velocity of light in the substance
1
1
1
x
=
D0
D1 f
image length
image distance
or
object length
object distance
Lens image equation:
Potential energy = weight of body x elevation
1
2
or amperes (I)
potential difference
resistance
volts or E
E
ohms
R
1 foot-candle: the illumination of any point on a surface 1 foot from
a standard candle.
Illumination(ft-c) = intensity (candles)
distance in feet2
Velocity of light = 186,000 miles per sec.
Acceleration of gravity =
Kinetic energy =
=
Light and Lenses
Acceleration = change of velocity
time
Centripetal force =
Ohm’s Law: Current
x
(velocity)2ac
Magnification =
Momentum = mass of body x its velocity
Mass
=
weight
acceleration of gravity
L
√G
Period of pendulum: T = 2π
Wave velocity = wave frequency x wave length, or v = nx1
Speed of sound: 1090 feet per second in air at 0 degrees Celsius.
Velocity of sound increases 2 feet per second for each degree Celsius
rise in temperature above zero degrees Celsius.
CALL:
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R
Conversions
Heat
Horsepower
To convert Fahrenheit to Celsius: subtract 32 from F, then multiply by
5
/9, written C = 5/9 (F-32). NOTE: Centigrade is now referred to as Celsius.
(NOTE: 212°F = 100°C). To convert Celsius to Fahrenheit:
multiply C by 9/5, then add 32, written F = (9/5 C) +32.
1 horsepower = 550 ft-lb sec
To convert Celsius to Absolute or Kelvin scale: add 273 to C.
Friction Constant =
force (lb) x distance (ft)
Horsepower =
550 ft-lb sec x time (sec)
friction force
weight
To convert Fahrenheit to Absolute or Kelvin scale: first convert F to C,
then add 273.
Work = force x distance moved
work
Boyle’s Law: p1 x V1 = p2 x V2 at constant temperature. Zero degrees
Kelvin is the lowest possible temperature.
Power =
In Kelvin Absolute temperature scale: water boils at 373K, freezes at
273K.
1 watt = 10,200 gram-centimeters per sec.
Charles’ Law:
V
1
V2
T
=
1
T2
at constant pressure
T1
=
1 kilowatt is 1000 watts
1 kilowatt is approximately 11/3 horsepower
Dyne is absolute metric unit of force. Erg is its unit of work.
1 Erg = force of 1 dyne acting through 1 centimeter
Combination of Charles’ and Boyle’s Laws:
V1p1
time
1 Joule = 10,000,000 ergs, or about 3/4 foot pounds
V2p2
The law of work when friction is neglected: effort force x effort
distance = resistance force x resistance distance Mechanical advantage
of a machine =
resistance force
T2
When heated through one degree Celsius,
any gas expands
1
273
effort force
of its volume at 0 degrees Celsius if the pressure remains constant. One
BTU is the heat required to raise the temperature of 1 pound of water
through 1 degree Fahrenheit.
When friction is zero, mechanical advantage of a machine:
effort distance
One calorie: the heat required to raise the temperature of 1 gram of
water through 1 degree Celsius.
Mechanical advantage of a lever =
Specific Heat: heat required to raise the temperature of a unit mass of
that substance through 1 degree. If H is total heat and M is mass,
H = M x s x (t2-t1).
Heat of melting or heat of fusion, L, is the quantity of heat needed to
melt one unit weight of substance without changing its temperature, or
H = M x L.
resistance distance
effort arm
resistance arm
Moment of force = force x lever arm
Frictionless mechanical advantage of an inclined plane
plane =
length
height
Frictionless mechanical advantage of a wheel and axle:
circumference of wheel
0 calories of heat is required to melt 1 gram of ice without raising
its temperature.
circumference of axle
Boiling point of liquid: that temperature at which the vapor pressure is
equal to the pressure above the liquid.
0.427 kilogram-meter (kg-m) = 1 calorie
Work
mechanical equivalent of heat
CALL:
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R
W
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R x I2
E
2
E
I
R x I2
R
OH
P
PxR
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TRANSCAT TECHNICAL REFERENCE
Conversion Tables
Engineering Constants and Conversions
Power
Physical Quantity…
British Thermal Units/Hour
British Thermal Units/Hour
British Thermal Units/Hour
Horsepower
Horsepower
Horsepower
Joules/Second
Joules/Second
Joules/Second
Kilowatts
Kilowatts
Kilowatts
Watts
Watts
Watts
Watts
(BTU/hr)
(BTU/hr)
(BTU/hr)
(Hp)
(Hp)
(Hp)
(J/s)
(J/s)
(J/s)
(KW)
(KW)
(KW)
(W)
(W)
(W)
(W)
Multiply By…
To Convert To…
0.393 x 10-3
0.2931
0.2931
0.746
2544.4
746.0
1.0
0.001341
3.412
1.341
1000.0
3412.0
0.001
0.001341
1.0
3.412
Horsepower
Joules/Second
Watts
Kilowatts
British Thermal
Joules/Second
Watts
Horsepower
British Thermal
Horsepower
Joules/Second
British Thermal
Kilowatts
Horsepower
Joules/Second
British Thermal
Multiply By…
To Convert To…
Units/Hour
Units/Hour
Units/Hour
Units/Hour
(Hp)
(J/s)
(W)
(KW)
(BTU/hr)
(J/s)
(W)
(Hp)
(BTU/hr)
(Hp)
(J/s)
(BTU/hr)
(KW)
(Hp)
(J/s)
(BTU/hr)
Area
Physical Quantity…
Square
Square
Square
Square
Square
Centimeters
Feet
Inches
Meters
Millimeters
(cm2)
(ft2)
(in2)
(m2)
(mm2)
0.155
0.0929
6.452
10.76
0.00155
Square
Square
Square
Square
Square
Inches
Meters
Centimeters
Feet
Inches
(in2)
(m2)
(cm2)
(ft2)
(in2)
Volume
Physical Quantity…
Cubic Centimeters
Cubic Feet
Cubic Feet
Cubic Feet
Cubic Inches
Cubic Meters
Cubic Meters
Cubic Meters
Cubic Millimeters
Gallons
Gallons
Liters
Liters
Milliliters
Multiply By…
(cm3)
(ft3)
(ft3)
(ft3)
(in3)
(m3)
(m3)
(m3)
(mm3)
(gal)
(gal)
(l)
(l)
(ml)
0.061
0.02832
1728.0
7.481
16.387
1000.0
264.18
35.31
61 x 10-6
231.0
3.7854
0.2642
1000.0
0.061
To Convert To…
Cubic Inches
Cubic Meters
Cubic Inches
Cubic Gallons
Cubic Centimeters
Liters
Gallons
Cubic Feet
Cubic Inches
Cubic Inches
Liters
Gallons
Milliliters
Cubic Inches
(in3)
(m3)
(in3)
(gal3)
(cm3)
(l)
(gal)
(ft3)
(in3)
(in3)
(l)
(gal)
(ml)
(in3)
Density
Physical Quantity…
Grams/Cubic Centimeter
Grams/Cubic Centimeter
Kilograms/Cubic Meter
Kilograms/Cubic Meter
Pounds/Cubic Foot
Pounds/Cubic Inch
Pounds/Cubic Inch
(g/cm3)
(g/cm3)
(kg/m3)
(kg/m3)
(lb/ft3)
(lb/in3)
(lb/in3)
CALL:
Multiply By…
To Convert To…
1000.0
0.03613
0.06243
0.001
16.018
0.5787 x 10-3
27.68
Kilograms/Cubic Meter
Pounds/Cubic Inch
Pounds/Cubic Foot
Grams/Cubic Centimeter
Kilograms/Cubic Centimeter
Pounds/Cubic Foot
Grams/Cubic Centimeter
800-828-1470
FAX: 800-395-0543
(kg/cm3)
(lb/in3)
(lb/ft3)
(g/cm3)
(kg/cm3)
(lb/ft3)
(g/cm3)
WEB: www.transcat.com
Conversion Tables
Engineering Constants and Conversions (Continued)
Speed/Velocity
Centimeters/Second
Feet/Minute
Feet/Second
Meters/Second
Miles/Hour
Miles/Hour
Multiply By…
(cm/s)
(fpm)
(fps)
(m/s)
(mph)
(mph)
0.03281
0.011364
0.3048
3.281
1.609
88.0
To Convert To…
Feet/Second
Miles/Hour
Meters/Second
Feet/Second
Kilometers/Hour
Feet/Minute
(fps)
(mph)
(m/s)
(fps)
(km/hr)
(fpm)
Volumetric Flow Rate
Physical Quantity…
Cubic Centimeters/Second
Cubic Feet/Hour
Cubic Meters/Minute
Gallons/Minute
Gallons/Minute
Multiply By…
(cm3/s)
(ft3/hr)
(m3/min)
(gpm)
(gpm)
To Convert To…
60 x 10-6
0.12468
264.18
0.06308
.22713
Cubic Meters/Minute
Gallons/Minute
Gallons/Minute
Liters/Second
Cubic Meters/Hour
Multiply By…
To Convert To…
0.03527
2.205
1000.0
2205
28.35
0.4536
453.6
907.18
Ounces
Pounds
Kilograms
Pounds
Grams
Kilograms
Grams
Kilograms
Multiply By…
To Convert To…
(m3/min)
(gpm)
(gpm)
(l/s)
(m3/hr)
Mass
Physical Quantity…
Gram
Kilogram
Metric Ton
Metric Ton
Ounces
Pound
Pound
Ton
(g)
(kg)
(oz)
(lb)
(lb)
(oz)
(lb)
(kg)
(lb)
(g)
(kg)
(g)
(kg)
Pressure
Physical Quantity…
Atmospheres
Atmospheres
Atmospheres
Atmospheres
Atmospheres
Atmospheres
Atmospheres
Atmospheres
Bar
Pounds/Square Inch
Pounds/Square Inch
(atm)
(atm)
(atm)
(atm)
(atm)
(atm)
(atm)
(atm)
(psi)
(psi)
1.01325
10,332.3
101,325.0
14.696
29.921
33.934
760.0
760.0
14.504
703.07
0.0703
Bar
Kilograms/Square Meter
Kilopascals
Pounds/Square Inch
Inches Mercury
Feet of Water
Millimeters Mercury
Torr
Pounds/Square Inch
Kilograms/Square Meter
Kilograms/Square Centimeter
(kg/m2)
(KPa)
(psi)
(in Hg)
(ft H2O)
(mm Hg)
(psi)
(kg/m2)
(kg/cm2)
Length
Physical Quantity…
Centimeters
Feet
Inches
Kilometers
Meters
Miles
Pounds/Cubic Inch
Multiply By…
(cm)
(ft)
(in)
(km)
(m)
(mi)
(P/in3)
CALL:
0.3937
0.3048
2.54
0.6215
3.281
1.609
0.03937
800-828-1470
To Convert To…
Inches
Meters
Centimeters
Miles
Feet
Kilometers
Inches
FAX: 800-395-0543
(in)
(m)
(cm)
(mi)
(ft)
(km)
(in)
WEB: www.transcat.com
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OH
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Physical Quantity…
S
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R
W
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R x I2
E
2
E
I
R x I2
R
OH
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PxR
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TRANSCAT TECHNICAL REFERENCE
Conversion Tables
Units and Conversion Factors
Linear Measure
Symbol
Unit
Inches
Per
Unit
Feet
Per
Unit
Yards
Per
Unit
Miles
Per
Unit
Centimeters
Per
Unit
Meters
Per
Unit
Kilometers
Per
Unit
in
ft
yd
mi
Linear inch
Linear foot
Linear yard
Linear mile
1
12
36
63360
0.0833
1
3
5280
0.027778
0.3333
1
1760
—
—
—
1
2.54
30.480
91.44
—
0.0254
0.3048
0.9144
1609.34
—
—
—
1.609
cm
m
km
Centimeter
Meter
Kilometer
0.3937
39.37
39370
0.0328
3.2808
3280.8
0.010936
1.093613
1093.613
—
—
.6214
1
100
—
0.01
1
1000
—
.001
1
Square Measure
Symbol
Square
Inches
Per
Unit
Unit
in2
ft2
yd2
—
cm2
m2
—
Square inch
1
Square foot
144
Square yard
1296
1
Acre
—
Sq. Centimeter
.15500
Square meter 1550.0031
Hectares
—
Square
Feet
Per
Unit
Square
Yards
Per
Unit
Acres
Per
Unit
Square
Centimeters
Per
Unit
Square
Meters
Per
Unit
0.006944
1
9
43560
0.0010764
10.76391
—
0.0007716
0.111111
1
4840
0.00011960
1.195990
11954.8
—
—
—
1
—
—
2.47
6.4516
929.034
8361.274
—
1
10000
—
0.000645
0.0929
0.836127
4047
0.0001
1
1000
Hectares
Per
Unit
Symbol
Unit
cu in
cu ft
cu yard
cu cm or cm3
cu m or m3
Cubic inch
Cubic foot
Cubic yard
Cu Centimeter
Cubic meter
1
1728
46656
0.0610237
61023.74
0.0001
1
e.g. 1 m3 = 1.307951cu yds, so
3 cubic meters would be (3 m3)
(1.307942 cu yd/m3) = 3.923853 cu
yd
Cubic
Feet
Per
Unit
Cubic
Yards
Per
Unit
Cubic
Centimeters
Per
Unit
Cubic
Meters
Per
Unit
.0005787
1
27
.0000353
35.31467
.00002143
.037037
1
.000001308
1.307951
16.387064
28316.847
764554.9
1
1,000,000
.000016387
.018317
.7646
.000001
1
e.g. 1 Liter = .26418 gallons, so 4
liters would be (4l) (.26418 gal/l) =
1.05672 gal
Liquid Measure
Symbol
Unit
Fluid
Ounces
Per
Unit
fl oz
—
l.qt
gal
l
Fluid Ounces
Pint
Quart
Gallons
Liter
1
16
32
128
33.814
Pints
Per
Unit
Quarts
Per
Unit
Gallons
Per
Unit
Liters
Per
Unit
.0625
1
2
8
2.1134
.03125
.5
1
4
1.0567
.0078125
.125
.25
1
.26417
.02957
.4732
.9464
3.7854
1
Weights
Symbol
gr
g
oz. t.
oz. av.
lb. t.
lb. av.
kg
—
—
Grain
Units
Troy
Grams Ounces
Per Unit Per Unit
Grain
1
.0648
Gram
15.4324
1
Ounce Troy
480
31.1035
Ounce Av. 437.5 28.3495
Pound Troy 5760
373.242
Pound Av.
7000
453.59
Kilograms
—
1000
Ton Metric
—
—
Ton Av.
—
—
Avoirdupois
Troy
Ounces
Pounds
Per Unit
Per Unit
.002083
.032151
1
.911458
12
14.5833
32.1507
32150.7
29166.7
CALL:
.002286
.035274
1.09715
1
13.1657
16
35.274
35274
32000
1) 640 Acres = 1 square mile
e.g. 1 square meter = 1.195990
square yards so 30 square meters
would be (30 m2) (1.195990
yd2/m 2) = 35.88 yd 2
—
—
—
0.4047
Cubic Measure
Cubic
Inches
Per
Unit
e.g. 1 meter = 3.2808 ft, so 300
meters would be (300 m) (3.2808
ft/m) = 984.24 ft
Avoirdupois
Pounds
Kilograms
Per Unit
Per Unit
.0001736
.002679
.083333
.075955
1
1.215278
2.67923
2679.23
2430.56
.0001429
.002205
.068571
.0625
.822857
1
2.20462
2204.62
2000
800-828-1470
Metric
Tons
Per Unit
—
.001
.031103
.028350
.37324
.45359
1
1000
907.185
Avoirdupois
Tons
Per Unit Per Unit
—
—
—
—
.000373
.000454
.001
1
.907185
e.g. 1 gram = .032151 troy
ounces, so 40 grams would be
(40 g) (.032151 oz.t./g) = 1.28604
oz.t.
—
—
—
—
.000411
.00050
.001102
1.10231
1
FAX: 800-395-0543
WEB: www.transcat.com
Conversion Tables
Decimals to
Millimeters
Fraction Decimal
mm
Fraction Decimal
/64
0.0156
0.3969
33
/64
/32
0.0312
0.7938
17
/64
0.0469
1.1906
35
/16
0.0625
1.5875
9
/64
0.0781
1.9844
/32
0.0938
/64
mm
0.5156
13.0969
/32
0.5312
13.4938
/64
0.5469
13.8906
/16
0.5625
14.2875
37
/64
0.5781
14.6844
2.3812
19
/32
0.5938
15.0812
0.1094
2.7781
39
/64
0.6094
15.4781
1
/8
0.1250
3.1750
5
/8
0.6250
15.8750
/64
0.1406
3.5719
41
/64
0.6406
16.2719
/32
0.1562
3.9688
21
/32
0.6562
16.6688
/64
0.1719
4.3656
43
/64
0.6719
17.0656
/16
0.1875
4.7625
11
/16
0.6875
17.4625
1
1
3
1
5
3
7
9
5
11
3
/64
0.2031
5.1594
45
/64
0.7031
17.8594
/32
0.2188
5.5562
23
/32
0.7188
18.2562
/64
0.2344
5.9531
47
/64
0.7344
18.6531
/4
0.2500
6.3500
3
/4
0.7500
19.0500
/64
0.2656
6.7469
49
/64
0.7656
19.4469
/32
0.2812
7.1438
25
/32
0.7812
19.8438
/64
0.2969
7.5406
51
/64
0.7969
20.2406
/16
0.3125
7.9375
13
/16
0.8125
20.6375
21
/64
0.3281
8.3344
53
/64
0.8281
21.0344
11
/32
0.3438
8.7312
27
/32
0.8438
21.4312
23
/64
0.3594
9.1281
55
/64
0.8594
21.8281
/8
0.3750
9.5250
7
/8
0.8750
22.2250
25
/64
0.3906
9.9219
57
/64
0.8906
22.6219
13
/32
0.4062
10.3188
29
/32
0.9062
23.0188
27
/64
0.4219
10.7156
59
/64
0.9219
23.4156
/16
0.4375
11.1125
15
/16
0.9375
23.8125
29
/64
0.4531
11.5094
61
/64
0.9531
24.2094
15
/32
0.4688
11.9062
31
/32
0.9688
24.6062
31
/64
0.4844
12.3031
63
/64
0.9844
25.0031
/2
0.5000
12.7000
1
1.0000
25.4000
13
7
15
1
17
9
19
5
3
7
1
CALL:
800-828-1470
Decimal
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.080
0.090
mm
0.0254
0.0508
0.0762
0.1016
0.1270
0.1524
0.1778
0.2032
0.2286
0.2540
0.5080
0.7620
1.0160
1.2700
1.5240
1.7780
2.0320
2.2860
0.100
0.110
0.120
0.130
0.140
0.150
0.160
0.170
0.180
0.190
2.5400
2.7940
3.0480
3.3020
3.5560
3.8100
4.0640
4.3180
4.5720
4.8260
0.200
0.210
0.220
0.230
0.240
0.250
0.260
0.270
0.280
0.290
5.0800
5.3340
5.5880
5.8420
6.0960
6.3500
6.6040
6.8580
7.1120
7.3660
0.300
0.310
0.320
0.330
0.340
0.350
0.360
0.370
0.380
0.390
0.400
0.410
0.420
0.430
0.440
0.450
0.460
0.470
0.480
0.490
7.6200
7.8740
8.1280
8.3820
8.6360
8.8900
9.1440
9.3980
9.6520
9.9060
10.1600
10.4140
10.6680
10.9220
11.1760
11.4300
11.6840
11.9380
12.1920
12.4460
FAX: 800-395-0543
Decimal
0.500
0.510
0.520
0.530
0.540
0.550
0.560
0.570
0.580
0.590
mm
12.700
12.9540
13.2080
13.4620
13.7160
13.9700
14.2240
14.4780
14.7320
14.9860
0.600
0.610
0.620
0.630
0.640
0.650
0.660
0.670
0.680
0.690
15.2400
15.4940
15.7480
16.0020
16.2560
16.5100
16.7640
17.0180
17.2720
17.5260
0.700
0.710
0.720
0.730
0.740
0.750
0.760
0.770
0.780
0.790
17.7800
18.0340
18.2880
18.5420
18.7960
19.0500
19.3040
19.5580
19.8120
20.0660
0.800
0.810
0.820
0.830
0.840
0.850
0.860
0.870
0.880
0.890
20.3200
20.5740
20.8280
21.0820
21.3360
21.5900
21.8440
22.0980
22.3520
22.6060
0.900
0.910
0.920
0.930
0.940
0.950
0.960
0.970
0.980
0.990
1.000
22.8600
23.1140
23.3680
23.6220
23.8760
23.1300
24.3840
24.6380
24.8920
25.1460
25.4000
WEB: www.transcat.com
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