# Tag Info

### Does doing work on system increase or decrease its internal energy?

If $\Delta V$ is negative due to compression of the gas, then the sign of the work is positive and the internal energy will increase. The convention used here is that the sign of the work done on a ...
• 3,232
1 vote

### What are the forces that do work when a spring between two masses pulls inwards?

There is no kinetic energy change in the second system (1,2, spring). So there is no net work done, so no need to ask which external forces that do the work. The constituent particles of the system do ...
• 51.5k

### Drawbacks of Quasi-Static process for lifting a block

And why do we need a quasi-static process to explain Potential Energy in the first place? We don’t. A quasistatic process is not required to explain potential energy. It is only a necessary condition ...
• 73.7k
1 vote

### Can siphons improve the efficiency of hydroelectric dams?

No, you cannot gain any efficiency. Remember the bernoulli equation: $P_1 + \frac12\rho v_1^2 + \rho gh_1 = P_2 + \frac12\rho v_2^2 + \rho gh_2$ If you have water at rest at $P_{atm}$ on the top, and ...
Accepted

• 10.6k

### Work performed by hydrostatic pressure

My intuition is that we are looking at a special case of Stokes' theorem, since we are relating surface integrals to volume changes. To this end, it seems clear enough to me that the differential ...
• 754

### Why the work done by surrounding on the piston is same as average work done by surrounding on the gas inside the cylinder?

But it's the work done on the PISTON. I will only address this statement, as some of your other statements are not clear (at least to me). There is no net work done on the piston unless (1) it ...
• 73.7k
1 vote

### The conservative force

While @basics has the math right, I understand your question is about the physical interptetation. To answer this, we must understand what a force field is, since the definition of the rotation ...
• 1,897
1 vote

### The conservative force

An example might be the best way to see it. Set up some electrodes that create a horizontal electric field. Make it so the field strength is proportional to height. This is a non-conservative field. ...
• 41.1k
1 vote

### The conservative force

Remark the curl it's the measure of the rotation of the vector field around a specific point Before answering your question, I'd replace (local) "rotation" with (local, or elementary) &...
• 10.6k

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