on 3/27/2002 12:34 PM, Ma Be at [EMAIL PROTECTED] wrote: > maybe we should go back to the basics to settle these questions, i.e. ask what > is a volt and a watt and write them both in terms of what they actually are > (i.e. in terms of the fundamental base units, like kg, m, s, etc),
It is useful to be able to write any derived unit in terms of basde units only, but often it is inconvenient to do so on a regualr and continuing basis. For example, the volt (V), in terms of SI base units, is equal a (kilogram)-(metre squared) per (ampere)-(second cubed). I think there is little doubt that we would all find it more convenient to call it a volt. Similarly, the watt is a (kilogram)-(metre squared) per (second cubed) and it is easier to call it a watt (or a joule per second). I agree that SOME units which are normally expressed as SIMPLE combinations of other units (base and/or derived) do NOT need special names. The special names may actually get in the way of understanding. The watt can be written as a joule per second (which is still equal to kg.m^2/s^3) and I think "joule per second" explains what power is all about better than giving it the special name "watt". The very fact that some people still think the amount of energy used has something to do with the number of hours is evidence of how confused people can get over the power concept. I attribute much of this confusion to the use of the watt. Regards, Bill Hooper physics professor (retired), Florida, USA ======================== Keep It Simple - Make It Metric! ========================
