Is F in P=F/A an average or a sum of all microscopic forces?

In summary, the force used in the pressure formula is an average of all microscopic forces exerted by the gas on the wall of the container over time. This means it is a sum over all particles, but an average over time to account for random fluctuations.
  • #1
Greg777
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Hello,
I've read that the force F we use in the pressure formula P=F/A is an average of all microscopic forces exerted by the gas on the wall of the container over a period of time. Is it true? I thought it was a SUM rather than an average?
I assume that in that definition the microscopic force is a force exerted by a SINGLE particle on the wall.
 
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  • #2
It's a sum over all the different particles, but an average over time. When the text talks about averaging, it should be talking about averaging over time to smooth out the random fluctuations of collisions with particles.
 
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Related to Is F in P=F/A an average or a sum of all microscopic forces?

1. What is the meaning of "F" in P=F/A?

The variable "F" in the equation P=F/A represents the force exerted on an object. This force can be due to various factors such as gravity, applied pressure, or other microscopic forces.

2. Is "F" an average or a sum of all microscopic forces?

It depends on the specific situation. In some cases, "F" may represent an average force, while in others it may be a sum of all microscopic forces acting on an object. It is important to consider the context of the equation to determine the meaning of "F".

3. Can "F" be a negative value in P=F/A?

Yes, "F" can be a negative value in the equation P=F/A. This indicates that the force is acting in the opposite direction of the chosen reference direction. It is important to carefully consider the signs and directions of all variables in the equation to accurately interpret the result.

4. How does "A" affect the value of P in P=F/A?

The variable "A" in the equation P=F/A represents the area over which the force is exerted. As the area increases, the pressure (P) decreases, assuming the force (F) remains constant. This is because the force is spread over a larger surface area, resulting in a decrease in pressure.

5. Is F in P=F/A a constant value?

No, "F" in the equation P=F/A is not a constant value. It may change depending on the magnitude and direction of the force acting on the object. It is important to consider all factors that may affect the force to accurately calculate the pressure (P).

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