basic energy formulas and equivalents.
energy is ability to do work. 1 newton of force over
1 meter is 1 newtonmeter or joule or watt second
of work done.
power is the rate of doing work. lifting 1 pound
weight
1 foot in one second is 1 footpound per second. if
you
lift 550 pounds one foot in one second that's 1
horsepower
of power required.
most people would have problem lifting 550 pounds
(249.48 kg),
directly. but you can lift that weight with a winch
over
longer time and the same amount of work was done, just
took
longer so required less power.
same principle with levers or pulleys. the force is
reduced
but distance the force is applied increases. so total
of
force * distance remains the same. (minus any friction
loss)
the same amount of work can be done by letting the
weight
fall, but then you have to do work to lift it back up.
1 btu = 252 calories
1 btu = 1055 joules (watt seconds) = .293 watt hours
1 btu raises 1 pound of water 1 degree fahrenheit
1 calorie raises a gram of water 1 degree celsius
1kilocalorie is used for diets = 1 kilogram water 1
deg celsius
1 calorie = 4.186 joules
1 therm = 100,000 btu = 29.3 kwh
1 ton of refrigeration = 12,000 btu/hr
1 lb residential garbage = 2,500 btu =0.73 kwh
1 lb coal = 13,000 btu = 3.81kwh 1ton=7.62 mwh
$1.31 per million btu = 0.44 cents per kwh
1 lb wood = 3,500 btu = 1.03 kwh
1 gal propane= 92,000 btu = 30 kwh
1 gal fuel oil= 138,000 btu = 40.45 kwh
($1.00 gallon = 2.5c/kwh)
1 cu. ft. nat. gas = 1,000 btu = .29 kwh
(44cent per 100 cuft=1.5c/kwh)
1 hp = 745.7 watts = 2545.3 btu hr
1 hp = 33,479 btuh (boiler)
1 hp = = 550 footlbs/sec = 33,000 footlbs/min
1 hp = 42.44 btu/min.
hp = torque in poundfeet x rpm/5252
(revolutions per minute /60) *2 *pi = radians/second
s rpm * 0.1047 = radians/sec
note: torque is measured in "foot pounds" but should
be described
as "pound feet" or 1 pound force at 1 foot radius to
avoid
confusion with work done lifting 1 pound 1 foot, unit
of energy.
1 joule = 1 watt second = 1 newton meter
energy is a scalar, with basic si units of
kgm^2/sec^2
(also defined to be the joule).
einstein's equation: e = mc^2 would be
for 1 gram of mass and c = velocity of light =3 * 10^8
meter/sec
1 * 10^3 kilograms * 9 * 10^16 = 9 * 10^13 joules
or 9 * 10^13/3.6 * 10^6 = 2.5 * 10^7 kwh.
kinetic energy of a moving mass is 1/2 * m * v^2
joules, m is mass in kg and v is velocity in
meters/sec.
momentum is a *vector*, with basic si units of
kgm/sec.
rotational momentum is p = j x w, where j is the
moment of inertia (same as used for calculating
rotational
kinetic energy).
ke of rotationally moving objects
equation ke = 0.5 x j x w^2, where j = moment of
inertia (rotational analog of mass, related to the
object's mass and its distribution around the axis of
rotation), an w = rotational speed, radians/second.
acceleration is the change in velocity/time
earth gravity acceleration is about 32 feet/sec^2
or 9.81 meters/sec^2. that means that velocity
of something falling without wind resistance or other
force, will increase 32 feet per second, every second
or 9.81 meters/second, every second. stopping or
deceleration is calculated the same.
v is velocity, d/t, meters/second or feet/second
d is distance
a is acceleration, change in velocity/time, m/s^2
t is time in seconds
v= at, t = v/a, a=v/t, d = 1/2at^2, t= 2d/v,
t = (2d/a)^0.5 {sqrt}, d = 1/2v^2/a,
a = 1/2v^2/d, v = (2ad)^0.5 {sqrt}
d = vt for constant velocity
using same units such as a = 32 feet per second^2,
in two seconds the distance traveled would be
1/2 * 32 feet/sec^2 * 2 sec^2 = 64 feet or
1/2 * 9.8 m/s^2 * 2 sec^2 = 19.6 meters
1 watt = 1 volt x 1 amp
1 amp = 1 coulomb of charge per second (6.02 * 10^23
electrons)
1 ohm = resistance that has 1 volt for 1 amp current
ohm's law
e for voltage, i for amperage, r for resistance ohms,
p for watts
e=ir, e=p/i, e=(rp)^0.5, i=e/r, i=p/e, i=(p/r)^0.5,
r=e/i,
r=p/i^2, r=e^2/p, p=ei, p=i^2r, p=e^2/r
1 watthour = 3.412 btu
1 kilowatthr = 3412 btu = 3.6 * 10^6 joule
1 kilowatt = 1,000 watts
1 kilowatt = 1.3405 horsepower
1 atmosphere = 14.7 lbs./sq. inch
1 atmosphere = 29.92 inches of mercury
1 pound per square inch = 6.899 kilopascals.
1 pascal is newton of force over 1 meter square,
pressure.
1 centimeter = .3937 inches
1 cubic foot = 1728 cubic inches
1 cubic foot = 7.48 gallons us
1 cubic foot/minute = 7.482 gallons/minute
1 cubic foot water = 62.4 lbs @ 60 deg. f
1 foot of water = .4333 lbs/sq. inch
1 footpound = .001286 btu
1 footpound = 1.356 newton meters
1 newton meter = 0.7376 foot pounds = 1 joule
1 newton accelerates 1 kg at 1 meter per second^2
(about 9.81 newtons = 1kg force in earth gravity)
1 foot/second = 0.68182 miles per hour
1 mph = 1.46667 feet per second.
1 meter/second = 3.6 kilometers/hour
1 meter = 39.37 inches = 3.28084 feet = 1.0936 yards
1 foot = .3048 meters
1 inch = 2.54 centimeters = .0254 meters.
1 gallon us = 3.785 liters = 231 cubic inches.
1 gallon us water = 8.35 lbs
1 inch of water = .03613 lbs./sq. inch
1 foot of water = 0.4335 psi
1 liter = 1.057 quarts
1 fluid ounce = 1.805 cubic inches
1 fluid ounce = .02957 liters
1 cubic inch = 16.387064 cubic centimeters
1 pound = 0.4536 kg or 1 kg = 2.2046 pounds
1 oz = 28.35 grams
celsius deg * 9/5 +32 = fahrenheit, f32 * 5/9 =
centigrade
212 deg fahrenheit = 100 degree celsius, water boils
32 deg fahrenheit = 0 degree celsius, water freezes
40 deg fahrenheit = 40 deg celsius
absolute 0 degrees or kelvin = 459.7 fahrenheit or
273 c
speed of light in a vacuum is approx 2.998 * 10^8
meters/second
or 186,000 miles per second. rounded off 3 * 10^8
meters/second.
1 megahertz frequency wavelength is 300 meters.
