Interesting Physics Question?

I believe you should add to your question:

1. The balloons are identical

2. A different amount of air was pumped into each balloon

3. The rubber in the balloon can be modeled as obeying Hooke's law if it is stretched in a particular direction, i.e., the stretch is proportional to the load

I'll let someone else answer this question. (It's a good one)

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I will agree and disagree with MD in part

B. True. It is indeed a surface tension problem. However, I would say that D is false. Air should immediately begin to pass between the balloons. They would start out with different internal pressures. If the balloons started out the same size with the same internal pressure, then MD would be correct because they would be in an unstable equilibrium. It is the pressure that drives the system.

G. I have total work done as positive. Work is done on the stretching of the larger balloon and on the net displacement of air when the big balloon expands (remember, pressure is now lower).

J. Entropy increases.

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MD,

I appreciate your excellent analysis.

We can agree that the speed of the flow will increase with time. My own thought is that we start out at a state which is non-equilibrium which means that some air will pass immediately. [The alternative would be to have two balloons of equal size (or different size but equal pressure) which would lead to no flow to begin with until the system gradually moves out of pressure equilibrium]. But ultimately, I think this difference between you and I is not in the physics, but in the analysis of what the question intends.

I say work is done because the bigger balloon will expand more than the smaller balloon will contract. This will not be by much, but it will happen.

Entropy would be lost in the throttling effect in the piping. Otherwise, you'd need some sort of turbine to collect the energy based on the pressure difference between the two balloons, Notwithstanding, I see your point.

Best regards.

This is the problem of surface tension of the material of the balloon.

Pressure of air in the balloon is inversely proportional to the radius.

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Only B), D), I) and L) are true

and A), C), E), F), G), H), J) and K) are false.

FGR

I considered the process to be slow because the pressure difference between the balloons will be small. Work done on the system is zero. Whatever +ve work is done by one balloon on another will be cancelled by negative work done on it. No net work is done by or on the balloons by any external agency. Theoretically, entropy increases is true, because for zero entropy increase, process has to be infinitesimally slow which it is not. So, I agree that selecting J) to be true in this case will be better. Of course, the increase in entropy will be so small that it can be ignored for practical purposes.

Edit:

FGR

Smaller balloon does work on larger balloon. Suppose this work is W This means work done on smaller balloon by larger balloon is - W. Net work done on the system = W - W = 0. This is so because work is not being done by any external agency. Inside the system, work done by one part on the system by another part does not result in any work done by or on the system and hence net work done in the process is zero. Smaller balloon loses energy and the larger balloon gains energy. It is just a transfer of energy from one part of the system to the other part which does not result in any work done on the system.

As far as entropy is concerned, you are right because for entropy change to be zero, the process will have to be infinitesimally slow which no practical process is. However, for practical purposes, change in entropy for a very slow process being small, it can be taken as zero. (Theoretically answer zero is incorrect.) Please note that this analysis is for entropy change of the system + surrounding.

stick with the exam i would say (A)

if given all those choice i might go with (J)

A,B,C,G,J