# Statistical Physics: Pressure Diff. in Moving Cylinder

• j93
In summary, the conversation discusses the difference in pressure within a cylindrical spaceship as it decelerates at a constant rate, with the acceleration parallel to its length and the air in thermal equilibrium. The suggestion is made to consider the factor e^{E/kT} and calculate the partition function, but it may not be necessary. It is also noted that the density of the air will scale in a similar way and conservation of mass is important. It is then questioned if statistical physics is needed and the suggestion to use dp=ro*g*dh is made.
j93

## Homework Statement

A spaceship that is cylindrical of area A and Length L decelerates at a constant rate a. The air treated. What is the difference in pressure due to the motion from the front to the back of the ship. The acceleration is parallel to L and air was in thermal equilibrium.

## The Attempt at a Solution

I believe intuitively there should be a factor $$e^{E/kT}$$ where $$E=W=Fx=max$$. I think I might need to calculate the partition function but it might not be necessary like when calculating $$V_{rms}$$ in passive circuit.

Last edited:
Your feeling is correct. Just remember that the density of the air will also scale that way, but you need to conserve mass/number.

Do you need statistical physics here? Why not use dp=ro*g*dh?

## 1. What is statistical physics?

Statistical physics is a branch of physics that uses statistical methods to study the behavior of large systems of particles. It aims to explain macroscopic properties of matter, such as pressure, temperature, and energy, by analyzing the microscopic behavior of individual particles.

## 2. What is pressure diffusion in a moving cylinder?

Pressure diffusion in a moving cylinder refers to the phenomenon of pressure changes occurring in a fluid-filled cylinder that is moving at a constant velocity. This is due to the differences in pressure and velocity between the front and back of the cylinder, which causes the fluid to flow and distribute pressure throughout the cylinder.

## 3. How is pressure diffusion related to statistical physics?

Pressure diffusion in a moving cylinder is a macroscopic phenomenon that can be explained using statistical physics. By analyzing the behavior of individual particles in the fluid, statistical physics can predict and explain the pressure changes that occur in the cylinder as a result of its motion.

## 4. What factors affect pressure diffusion in a moving cylinder?

The velocity of the cylinder, the properties of the fluid (such as viscosity and density), and the dimensions of the cylinder all affect pressure diffusion. In addition, the temperature and pressure of the fluid may also play a role in the diffusion process.

## 5. How is pressure diffusion in a moving cylinder measured or calculated?

Pressure diffusion in a moving cylinder can be measured by using pressure sensors placed at different points along the cylinder. The pressure readings can then be used to calculate the pressure difference and diffusion rate. Alternatively, theoretical models based on statistical physics principles can be used to calculate the pressure diffusion in a moving cylinder.

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