On 28/10/2007 11:41 AM, Stephen A. Lawrence wrote:
> Speed is not power. Power is speed times force.
>
> Torque is not power. Power is rotational velocity times torque.
>
> A simple lever can produce more _force_ than is applied to it, and a
> simple chain and gear drive -- such as on my bicycle -- can produce far
> more _speed_ at the output (the wheel) than the input (my feet on the
> pedals).
>
> What's more, a capacitor can produce far more _power_ out than _power_
> in ... but only for a little while. The interesting question isn't
> whether the machine can produce a lot of "speed" or "torque" or "force"
> or even "power" -- the question is whether total /energy/ out is larger
> than total /energy/ in.
Why is energy more important than power?
Consider this hypothetical system:
input power ---> gross output power out ---> net output power
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| |
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------<------------
If the net output power exceeds the input power doesn't this qualify as
"over unity"?
Harry
