Pressure exerted by a gas (derivation using the kinetic theory of gases)

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SUMMARY

The discussion focuses on deriving the pressure exerted by a gas using the kinetic theory of gases, specifically addressing the time between collisions of gas particles with a wall. The time interval, represented as ##\Delta t = {2L\over |u|}##, is crucial for calculating the average force exerted by gas molecules on the wall. Participants emphasize that the average force is determined by the change in momentum over this time period, rather than the instantaneous force during the brief collision. The conversation highlights the importance of understanding these concepts for accurate calculations in gas dynamics.

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Bheshaj
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In the derivation of finding pressure exerted by a gas using kinetic theory of gases I am not understanding why the time between two collisions is taken as the time for rate of change of momentum when a particle bounces back from the wall. please help me
 
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I think you misquote. Any reference ? The duration of the collision with the wall is the time in which the momentum changes.
 
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BvU said:
I think you misquote. Any reference ? The duration of the collision with the wall is the time in which the momentum changes.
BvU said:
I think you misquote. Any reference ? The duration of the collision with the wall is the time in which the momentum changes.
see this
 

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Something gave in in my neck when I tried to read this. Have to go to the hospital first ...

So where is this quote ? I see ##\Delta t = {2L\over |u|} ## for the time to go to the left wall and back again ...
 

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Here in the lower left corner its given that force is change in momentum upon time. where he writes the change in momentum and divides it by time between two collisions as given above it.
 

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They don't have a microscope here in the hospital to read your fine print. Can you be bothered to learn some ##\LaTeX## in order to post legibly ?
 
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But if I have to guess he now averages the change in momentum from the gas particles that bump into the wall, to calculate the average force on the wall.
 
Its because yoy want to find average force exerted by the molecule. How u find average force? See u find the time in which this repears aka time period. The collision with wall PQRS repeats. Now find the average force in this time. If u were to find instantaneous force u have to divide by time of collision which is very small.

You are giving Maharashtra HSC? I am also giving it.
 
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Mohammed Ayaz Quadri said:
Its because yoy want to find average force exerted by the molecule. How u find average force? See u find the time in which this repears aka time period. The collision with wall PQRS repeats. Now find the average force in this time. If u were to find instantaneous force u have to divide by time of collision which is very small.

You are giving Maharashtra HSC? I am also giving it.
yeah, me too thanks
 
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BvU said:
But if I have to guess he now averages the change in momentum from the gas particles that bump into the wall, to calculate the average force on the wall.
thanks
 

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