27 Jul
2012
27 Jul
'12
12:33 p.m.
I was surprised to see on an Irish cooking show,
liquid measure in
decilitres (a practical unit for the job), but measure by weight in
That would be very uncommon in England. Most of the time, liquid voluems
are given in 'cc' (cubic centimetres == millilitres to this accuracy).
Althoguh for some unknown reason, most wine bottles (not that I eey buy
such stuff() are labelled as 75cl (not 75ml). Go figure.
'Deci' and 'Deka' are not commonly-used prefixes in England. One time I
do come across them is that tightneing torques are now often givein in
dekanewton.metres. The reason for that is that they used to be given in
kg.m (or more correctly kgf,m), and to this accurage, g=10m/s^2. Hence
the numeric values all remained the same. And actually, what is normally
important when tightneing soemthig nis that he bolts are _about_ the
right tightness, but more importantly all are the same (so that the
clamping force is even over a cylinder head or something). In which case
the approcimation is fine.
I think I've mentioend this before, but both torque and work have the
dimensions of force * distance (e.g. Newtons * metres). But while it is
correct to say that a newton metre of work is a joule, it is incorrect to
do the same for torque. What is the fundamental difference?
-tony