# Recent content by nasu

1. ### A Equipartition of energy in the modes of a resonant cavity

The equipartition of energy is seen in a system at thermal equilibrium. This is the necessary condition and is assumed for a black body cavity.
2. ### B How can a reaction force do work on someone who is jumping?

The change in kinetic energy of a system can be produced by the work of internal forces too. Review the work-energy theorem for a system of bodies with internal forces. It's the momentum that cannot be changed by internal forces but not so for KE.
3. ### B What is the meaning of the word "resolved"?

This is the meaning associated with the word "resolution". As in the resolution of a microscope or other instrument.
4. ### Draw the F.B.D. (Free Body diagram) of two blocks

Your FBD is almost correct. Just that F is horizontal and not vertical. The force acting vertically on the the small body is the tension in the string. As the pulley is rigidly connected to body 2, F acts horizontally on body 2. This is where is supposed to be in the FBD, if you split the...
5. ### Draw the F.B.D. (Free Body diagram) of two blocks

You don't need to analyse the bodies separately to answer the question. Just consider the system and the horizontal external forces. The body 2 had no vertical acceleration.
6. ### B Will graphene becomes a wonder material for future inventions?

It may be that you misread the forum title as "psychic forums"? :smile:
7. ### I Possible Error in Goldstein's Classical Mechanics 3rd Edition

Thank you. Google did not suggest it when I was looking for vasconomic. :) It does not know everything. Yet.
8. ### I Possible Error in Goldstein's Classical Mechanics 3rd Edition

What is the meaning of "vasconomic"? Google did not give any hit for vasconomic dynamics.
9. ### A Does electron energy contribute to current

I think you are confusing thermal phenomena with electrical conduction. Only electrons withing a few $k_B T$ contribute to the electron heat capacity. There is no such a requirement for electrical conduction. After all the expression for electrical conductivity contains the total free...
10. ### B Is there any physical quantity having two different units?

If they had different formulas, different units and apply to different conditions, by what logic would you even call them "the same quantity"?
11. ### Using acceleration to find tension (concept problem)

The tension acts on both objects not just on one of them. It is an internal force if you consider the system of the two objects.
12. ### B Basic Algebra Question: 3x = 15

It's a good option when you are familiar with the algebra. May not be so good when someone struggles to understand the general procedure.
13. ### B Is relativity universal?

Even your assumption that "temperature is relative" needs some explanation. Maybe you can explain what do you think "relative temperature" means. The sensations of cold and hot are "relative" in the sense that what one person calls cold may be hot for another or what we call warm weather in...
14. ### B Is relativity universal?

You may have the wrong idea about what theory of relativity is. Your example with temperatures does not have any relation to the purpose of the theory of relativity. It is not even an example of a "relative" quantity in the common sense of the therm.
15. ### B Basic Algebra Question: 3x = 15

Why do you need to factor 15? What if it si 3x=16?