Robert Bushnell wrote in USMA 20994:

>                    2002 July 12
>Madan;
>        In 20959 you tell Claire to give energy in units of TWH.
>
>This is wrong.  The watt hour is allowed only for electricity.
>
>Energy is given in multiples of joule.
>
>Further, the symbol for hour is h,  not H.
>
>                    Robert Bushnell


Nonsense!  The watt is the SI derived unit for all kinds of power -
mechanical, electrical or thermal.  Agreed that the joule is the SI derived
unit of energy and is equal to the watt second, again not exclusively
electrical.  The watt hour is a non-SI unit accepted for use with the
International System.  The amp�re is the SI electrical base unit and all SI
electrical derived units involve the amp�re.

Joseph B.Reid
17 Glebe Road West
Toronto  M5P 1C8             Tel. 416 486-6071

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