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<a href="todo.html" >Todo list</a>
<span style="white-space: pre; font-size:20px;">
Install
To finish install on phone, click Send-To, Add to Home Screen. The calculator
should now fill the screen in landscape orientation.
Introduction
The physical calculator is intended to help solve physics problems. Unlike a
conventional calculator, this calculator works with measurements. A measurement
has a numeric value as well as a unit (such as meters, kilograms or seconds).
Units are carried through a calculation, so if you take 20 m (meters) and
divide it by 5 s (seconds), the results would be 4 m/s (a speed). Or if you
cube a length like 0.1 m, the result would be 0.001 m^3 (a volume of 1 liter).
Just like when you solve physics problems on paper this helps ensure sensible
answers. However for this calculator, it also helps provides several other
features. All units are handled internally as SI units, in this way conversions
are easily done, constants only need to be provided in one common form and
formulas also only need to be provided in one form.
General
Buttons are mostly similar to a TI scientific calculator.
Math operations happen to both the value and the unit. Multiplying and dividing
combine the units of the two operands. Adding must be done with identical units.
Operations that result in non-sensible units, such as square root of a volume
are not allowed. Operations such as sin or log can only be done on scalars
(numbers with no units).
Units
To enter a measurement with a unit, enter a number, then press the 'unit'
button. The 'unit' button shows a list of most commonly used units. The units
are arranged largely in rows, length, mass, time, electrical, temperature.
Units are multipled as they are entered. Pressing 'm' once will be a length in
meters. A second time becomes m*m (shown as m^2), an area. A third time m^3, a
volume. Pressing 'unit' again will exit unit mode.
To enter a ratio'd unit such as speed:
enter the numeric value
press 'unit'
press a length such as 'm'
press the '1/un' key, note how the diamond cursor moves to the denominator
press a time such as 's'
press 'unit' again to exit the unit mode
Units can be editted by using the '1/un' key to cancel out units. For example
m^2 can be changed to m by pressing 1/un and then m. The numerator and
denominator m's cancel out leaving m. Press '#' to remove all units (convert to
scalar).
Conversions
The unit screen can also be used to handle unit conversions. If a unit type
such as 'kg' already exists, but a different unit of the same dimension,
(in this case mass) is pressed such as 'oz', the value will be converted to
the new unit. This works for more complex units also, such as m/s being changed
to mi/h.
The SI+ key can be used to cycle between various SI unit forms of complex units,
for example, W cycles between J/s, A V and kg m^2 / s^3, see list of derived units
below for details.
Constants
The 'cnst' button shows a list of useful constants. The 'list' button shows
additional constants. Pressing 'cnst' again returns to normal mode without
entering a constant.
Implicit formulas
An automatic solver (using dimensional analyis) will solve simple physics
problems that don't require any physical constants. This includes ohm's laws,
speed/distance/time problems and similar.
For example, enter the following:
'20', 'unit', 'm', '1/un', 's', 'kwn' (given a speed of 20 m/s)
'5', 'unit', 'm', 'kwn' (and given a distance of 5 m)
'unit', 's', 'unkn' (how long would it take to travel)
Note - for the unknown, the value is ignored, onlty the units are significant.
Pressing 'list' (followed possibly by the 'implicit' button) will show the
formula used to perform the calculation.
Explicit formulas
For more complex problems, the explicit solver searchs a library of physical
formulas to provide a solution. It works identically to the implicit solver.
Some implicit correct formulas are also included in explicit form to put a
name to the physical law and assist in showing the result is correct.
When 'list' is pressed and 'explicit' is selected, multiple solutions may be
provided. These can be scrolled through using the arrow keys provided.
Missing and Extra will show partial matches with missing or extra terms to
assist in finding the correct formula.
Keyboard shortcuts (for PC use)
0-9, ., +, -, *, /, =, (, ), E(for EE), M(for +/-), Escape(for CE/C), Enter(shortcut for =)
Derived and complex units
hertz frequency Hz, 1/s
steradian solid angle sr, rad2
newton force, weight N, kg m/s2
pascal pressure, stress Pa, N/m2, kg/m s2
joule energy, work, heat J, m N, C V, W s, kg m2/s2
watt power, radiant flux W, J/s, V A, kg m2/s3
coulomb electric charge or quantity of electricity C, F V, s A
volt voltage, electrical potential difference, electromotive force V, W/A, J/C, kg m2/s3 A
farad electrical capacitance F, C/V, s/Ω, s4 A2/kg m2
ohm electrical resistance, impedance, reactance Ω, 1/S, V/A, kg m2/s3 A2
siemens electrical conductance S, 1/Ω, A/V, s3 A2/kg m2
weber magnetic flux Wb, J/A, T m2, V s, kg m2/s2 A
tesla magnetic induction, magnetic flux density T, V s/m2, Wb/m2, N/A m, kg/s2 A
henry electrical inductance H, V s/A, Ω s, Wb/A, kg m2/s2 A2
lumen luminous flux lm, cd
lux illuminance lx, lm/m2, cd/m2
becquerel radioactivity (decays per unit time) Bq, 1/s
gray absorbed dose (of ionizing radiation) Gy, J/kg, m2/s2
sievert equivalent dose (of ionizing radiation) Sv, J/kg, m2/s2
katal catalytic activity kat, mol/s
newton second momentum, impulse N s, m kg/s
newton metre second angular momentum N m s, m2 kg/s
newton metre torque, moment of force N m, m2 kg/s2
newton per second yank N/s, m kg/s3
joule second action J s, m2 kg/s
joule per kilogram specific energy J/kg, m2/s2
joule per cubic metre energy density J/m3, kg/m s2
newton per metre surface tension, stiffness N/m, J/m2, kg/s2
watt per square metre heat flux density, irradiance W/m2, kg/s3
pascal second dynamic viscosity Pa s, N s/m2, kg/m s
watt per steradian square metre radiance W/sr m2, kg s3
watt per steradian cubic metre spectral radiance W/sr m3, kg m s3
watt per metre spectral power W/m, m kg/s3
gray per second absorbed dose rate Gy/s, m2/s3
watt per cubic metre spectral irradiance, power density W/m3, kg/m s3
joule per square metre second energy flux density J/m2 s, kg/s3
reciprocal pascal compressibility 1/Pa, m s2/kg
joule per square metre radiant exposure J/m2, kg/s2
newton metre second per kilogram specific angular momentum N m s/kg, m2/s
watt per steradian radiant intensity W/sr, m2 kg/s3
watt per steradian metre spectral intensity W/sr m, m kg/s3
coulomb per square metre electric displacement field, polarization density C/m2, s A/m2
coulomb per cubic metre electric charge density C/m3, s A/m3
siemens per metre electrical conductivity S/m, s3 A2/m3 kg
farad per metre permittivity s3 A2, s4 A2/m3 kg
henry per metre magnetic permeability H/m, m kg/s2 A2
volt per metre electric field strength V/m, m kg/s3 A
coulomb per kilogram exposure (X and gamma rays) C/kg, s A/kg
ohm metre resistivity Ω m, m3 kg/s3 A2
coulomb per metre linear charge density C/m, s A/m
joule per tesla magnetic dipole moment J/T, m2 A
square metre per volt second electron mobility m2/V s, s2 A/kg
reciprocal henry magnetic reluctance 1/H, s2 A2/m2 kg
weber per metre magnetic vector potential Wb/m, m kg/s2 A
weber metre magnetic moment Wb m, m3 kg/s2 A
tesla metre magnetic rigidity T m, m kg/s2 A
metre per henry magnetic susceptibility m/H, s2 A2/m kg
lumen second luminous energy lm s, s cd
lux second luminous exposure lx s, s cd/m2
candela per square metre luminance cd/m2, cd/m2
lumen per watt luminous efficacy lm/W, s3 cd/m2 kg
joule per kelvin heat capacity, entropy J/K, m2 kg/s2 K
joule per kilogram kelvin specific heat capacity, specific entropy J/K kg, m2/s2 K
watt per metre kelvin thermal conductivity W/m K, m kg/s3 K
kelvin per watt thermal resistance K/W, s3 K/m2 kg
</span>