Me and my friend are trying to find the exact unit of Power=Pressure/Volume. We know that the unit has to be W(J/s) so we try from the equation above: (Kgm²/s³)=(N/A)/V The right side will be: (Kgm/s²)/m^5 Then, Kg/(s²m⁴) So at the end: (Kgm²/s³) ≠ Kg/(s²*m⁴). Are we missing something?

We know we can get the exact unit using: W=F×x ==> F=W/x And etc... But we want to know why the first way is wrong? The example we are trying to solve

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    $\begingroup$ power$\ne$pressure/volume but work = pressure $\times$ volume $\endgroup$ – Farcher Nov 22 '18 at 9:20
  • $\begingroup$ Even if we say that W=P/V. (Kg*m²/s²) = (N/A)/V... The final result will be the same as above, the m⁴ wil still down $\endgroup$ – GalaxyLimits Nov 22 '18 at 9:29
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    $\begingroup$ Malwarebytes blocks the website in your link for me. As @Farcher says, you can't get this to work out, because "Power = pressure/volume" is just plain wrong. $\endgroup$ – alephzero Nov 22 '18 at 9:41
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    $\begingroup$ Power=Pressure/Volume is wrong, and you have taken W=P/V as argument in your comment,whereas it should be W=P*V. $\endgroup$ – Blazar Nov 22 '18 at 9:48
  • $\begingroup$ Oh, I see! Our doctoe told us something like a relation between Power and pressure over volume and in his slides (the one that he have) the relation is wrong. Thank you all for the answer. $\endgroup$ – GalaxyLimits Nov 22 '18 at 10:09

Power=Pressure/Volume is an incorrect relation.

To put it simple :Power is defined as "Rate of doing work" https://en.wikipedia.org/wiki/Power_(physics)

Which means,the dimension of power is J/s or (Kg*m^2/(s^2)).

Whereas the dimension of Pressure/Volume is Kg/(s^2*m^4)).

The first method is wrong because, Power=Pressure/Volume is just plain wrong. No such relation exists.

  • $\begingroup$ Or you could say that,power has units of Pressure*Volume/time which is not equal to the unit of pressure/volume. So Power is not equal to Pressure/volume. $\endgroup$ – Blazar Nov 22 '18 at 10:07

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