Quote:
Originally Posted by Besoeker
Not so. It is a rate of doing work.
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Power is a derived rate of Work / time. If time is zero, you cannot derive a value for power and work cannot be done, except it can be observed for that moment in time, which is implied rather than actual, on the basis that at the next instance of time, work will continue. This gives practical meaning to instantaneous, because in mathematical terms zero time passes at an instant. Work must be done for power to have meaning, but work cannot be done if zero time passes, but it can be observed as having been done, at that moment in time.
Quote:
Originally Posted by Besoeker
Incorrect at that point. Power is the rate of doing work. If that rate is performed over zero time there is no work.
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That's what I indicated. And, if no work is done, power cannot be derived except for the reason I explained above.
If velocity has any meaning, with regard to wind energy, at any instant kinetic energy content per unit area exists. Therefore energy in motion ( wind ) can be instantaneous, when measured at a given moment. In that respect it's no different to power as described above.
Energy is present all the time. Energy does not have to be doing work to exist. Power on the other hand is the rate at which energy is transmitted or work done, but for work to be done, energy has to be transferred. The mere meaning of transferred implies past tense and therefore implies the passing of time and hence past of the current moment. For energy to be transferred, time must pass, yet in an instant, no time passes and we can only observe what has gone before. Thus instantaneous power is more of an observation or measurement of what has occurred, but viewed in an instance or a moment, without passage of time. Energy however is always present and instantaneous and in some ways more so than power.