Units

Every number in Beermat can carry a unit, and the units travel through the calculation with it.

As text

F := 2.5 kN
A := 25 mm*40 mm
σ := F/A = ?

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Typing units

A unit goes straight after its number: 6 m, 12 kN/m, 8360 cm^4. In the editor you needn’t type the space: 6m becomes 6 m. A unit is just a name multiplied by the number, so compound units are written as you would on paper: kN*m, m/s^2, kg/m^3.

The units reference lists every built-in unit: SI with its common prefixes, US customary units, and a few others (bar, t for the tonne, L for the litre).

Showing a result in another unit

With no unit asked for, Beermat picks one from SI, with the prefix that keeps the number readable:

As text

v := 90 km/hr
t := 2 s
a := v/t = ?

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To see a result in a unit of your own, type the unit after the =. It goes into the placeholder at the end of the result and stays there:

As text

σ = ? psi
v = ?
E_day := 3 kW*8 hr = ? kW*hr
E_day = ? MJ

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Any unit of the right kind works; the calculation inside doesn’t change, only what is shown.

The mistakes units catch

Adding a length to a time is almost always a typo or a missing term. Beermat refuses it and says why:

As text

x := 3 m + 2 s

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The letters are the dimensions: L length, M mass, T time, I current, Θ temperature, N amount of substance, J luminous intensity. A wrong unit in the placeholder is caught the same way:

As text

σ = ? kN

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Things of the same kind mix freely: 3 m + 250 mm is 3.25 m.

Gravity, grams and other clashes

A few unit names are also common variable names. Beermat settles them like this:

• g is standard gravity, 9.80665 m/s². The gram is the upright g, a different name: type g, then Ctrl+I, which turns a plain (italic) name upright. In a file it is written \rm g (name styles). kg and mg are as usual.
• L is the litre, t the tonne, m the metre, s the second.

You can still use these names for your own variables: L := 6 m makes L the span from there on. But a unit you redefine is no longer that unit below it. After m := 5, 3 m is 15, not three metres. If a result suddenly looks wrong by a large factor, look for a variable named like a unit.

As text

m := 2 kg
w := m*g = ?

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Angles

Angles are plain numbers in radians, and deg is π/180:

As text

θ := 30 deg
sin(θ) = ?
θ = ?
θ = ? deg

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To make angles a dimension of their own, so that a rotation can’t be added to a length, see Angles and money as dimensions.

Temperatures

°C and °F are scales: 20 °C is the temperature 293.15 K. A difference of temperatures is in kelvin, or Δ°C:

As text

T := 20 °C
T = ?
T = ? °C
T = ? °F
ΔT := 30 °C - 20 °C = ?
ΔT = ? Δ°C

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Inside a compound unit, °C is a degree of difference: a conductivity in W/(m*°C) means what it says.

Your own units

A unit of your own is a definition like any other, usable below it:

As text

bag := 25 kg
cement := 12 bag = ?

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Taking the unit off

To use a value where a plain number is needed (in a lookup table, or a formula from a code that assumes units), divide by the unit:

As text

v := 12 kN/m
v/(1 kN/m) = ?

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