376
EXTENSION OF THERMODYNAMIC COMPUTATIONS
go (2. - *>) = - Cfa (T a - To) = - Pl ^ - è fo» - ?0 >) -
pl 0
ffil - <2o)
must satisfy the dimensions of all these terms, as well as the
equations P = pRT, and (&- Q 0 ) = (Wi - W 0 ) + (JJ X - U 0 ).
(Qi ~ Qo) was derived from - (Cp a - Cp w ) (T a - T 0 )
+ | (<7i 2 — <7o 2 ) = — (Qi — Qo) so that it has the same dimensions
D k- i _ , . „ P Pv
as K = —Cp, and since R = they are the same
as those for work, (Wi - Wo) = Pw {vi - v 0 ), and for the
inner energy (JJx — U 0 ) = Cv (T a — T 0 ). In transformations
from the (M. K. S.) to the (C. G. S.)system the dimension factors
are, [.M] = 1000 = 10 3 , [.L\ = 100 = 10 2 ; in transformations
from the (C. G. S.) to the (M. K. S.) system, [M] = 10~ 3 ,
[L] = 10 2 . All are in mechanical units.
(4) Gravity in meters/sec, [g 0 ] = L) , ,
(Zi - zo) meters, [z, - z 0 ] = L J go {Zl ~ z °> = L = W = * • •
Pressure, kilog./met. 2 , [Pi~P 0 ] = ML~ 1 ? [~Pi-P 0 ~| _
Density, kilog./met. 3 , [Pi 0 ] =ML~ 3 ) L P 10 \ L ~
Velocity square, [gi 2 — g 0 2 ] = L 2 = 10 4 = ,
10 4
Specific heat, [Cp, Cv, R. K.\ = L 2 = 10 4 =
Heat, [Qi - Qo = (Cp a - Cp 10 ) (T a - To)] = L 2 = 10 4 =
Work, [{Wx - W 0 ) = P 10 (vi - I*,)] = ML- 1 . M- 1 L 3 — L 2 = 10 4 =
Inner Energy, [(Z7i - U 0 ) = Cv (T a - P 0 )] = L 2 = 10 4 =
= 10000
= 10000
= 10000
= 10000
= 10000
= 10000
= 10000
The common factor for reducing all the terms of the gravity
and heat equations from (M. K. S.) to (C. G. S.) in mechanical
units is 10 4 = 10,000.
From the general equations (Wi — Wo) = Pi o (vi—vo) and
(Qi — Qo) = (Wi — Wo) + (Ui — U 0 ), we have,
K
10
Ui-Uo
vi - Vo
Qi ~ Qq
vi - Vo
- P10
r d
which is the radiation equation employed in the computations.
The dimensions of all these terms are the same in reducing from
the (M. K. S.) to the (C. G. S.), the factor being
10000
= 10, as
1000