Originally Posted by mathman
Originally Posted by Slim1754
Originally Posted by mathman
Originally Posted by Slim1754
Apparently you don't have the iq to understand that velocity DOES NOT EQUAL pressure. It can be an indicator, but only when variables don't change.
PRESSURE OVER TIME minus whatever resistance the bullet encounters, blowby, etc. Determines velocity.


Not quite. The work done by an expanding gas is pressure as a function of volume, integrated over volume.

w = ∫p(v)d
fine then, area under the curve, which I mentioned previously. if you get what I am saying, why bring calculus into it?
Thanks for trying to explain it to RDW though.

This can be parameterized using time t, but the pressure-time curve by itself doesn't tell the story.


Please put your comments outside of the quote box, or color them, so I can follow them better.

It's area under the curve all right, but you still haven't latched on to the fact you're talking about the wrong curve. Work done, and hence velocity, is through the area under the p-v curve, not the p-t curve.

Calculus was brought in precisely because that's how area under curves is described in other than simple situations.

Well, this is a simple situation where i was trying to keep an explanation simple. what am i missing? pressure times the area is force. simply put, the average force (however you want to arrive at that) exerted over the time the bullet is in the barrel will give velocity when bullet weight acceleration are figured. BTW The area under a curve with pressure in the y axis and time in the x-axis will give the work done on the bullet. what is it you think I am not latching on to? - how to open up my physics book and write some equations? Thanks for your "help"

Last edited by Slim1754; 04/20/15.
60 percent of the time, it works every time