One prediction on electric cars

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Besoeker

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What the watt definition specifically states:
Consider the watt definition. The word "instantaneous" is not used so there is no valid reason to think it is implied. If we want to be picky and look closely at the definition, we will notice it is actually a unit value so we have a unit of work over a unit of time. We have one Joule of work expended/converted/exchanged over one second of time (J/s).

One second is hardly instantaneous.

And this is the point you don't seem to comprehend.
Sixty miles per hour doesn't mean you have to drive for an hour.
It isn't about duration.
 

mivey

Senior Member
And this is the point you don't seem to comprehend.
Sixty miles per hour doesn't mean you have to drive for an hour.
It isn't about duration.
Yes, I get that. In the limit the duration can become an instant.

What you seem to miss is that does not hold true for the periodic signal when we measure the active power. We measure in multiples of cycles. We can measure down to the one cycle duration. Beyond that we no longer get the active power. The measurement of real AC power has a minimum duration we can use and it is not an instantaneous value.

We can however find a standard watt quantity measured over one cycle to get a rate of one Joule per second.
 
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mivey

Senior Member
In the limit the duration can become an instant.
It isn't the limit. It is the actuality.
Still unable to back up your opinions I see.

As you don't seem to understand how, let me give you yet another example:

From the IEEE dictionary:

watt: The watt is the power required to do work at the rate of one joule per second.

rate: The change in a value over a specified period of time. Note: Instantaneous rate is the derivative of the value with respect to time and cannot generally be measured. The measured rate approaches the instantaneous rate as the specified period of time approaches zero.
 

Besoeker

Senior Member
Location
UK
Still unable to back up your opinions I see.

As you don't seem to understand how, let me give you yet another example:

From the IEEE dictionary:

watt: The watt is the power required to do work at the rate of one joule per second.

rate: The change in a value over a specified period of time. Note: Instantaneous rate is the derivative of the value with respect to time and cannot generally be measured. The measured rate approaches the instantaneous rate as the specified period of time approaches zero.
All of which exactly supports my point.

One joule per second is a rate. Not a duration.
 

mivey

Senior Member
Besoeker,

I'm tired of posting info on this. Unless someone has a specific question, I think there is enough here already for anyone who is interested.

See you later.
 

Besoeker

Senior Member
Location
UK
You still aren't reading. The beginning of knowledge...
Try reading the very definition YOU posted:

watt: The watt is the power required to do work at the rate of one joule per second


In an AC circuit, it varies from one instant to the next. It is an instantaneous value.
I'm sorry if you can't/won't see that.
Here is my nice piccy again.

1V1A1W_zps788ce72e.jpg

Now I really am done with this - I've tried and have no wish to further protract a discussion that threatens to become acrimonious.
 
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