Topic about masses (modern physics)

AI Thread Summary
The discussion revolves around a physics problem regarding the mass of a system composed of n freely moving particles. The initial claim suggests that the total mass of the system equals the sum of the individual masses of the particles. Participants clarify that the statement is incorrect, particularly when considering particles like photons, which have zero rest mass. A counterexample is requested to demonstrate the fallacy of the original claim. The conversation emphasizes the importance of understanding particle types in relation to mass in modern physics.
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Homework Statement


If a system is composed of n particles that are freely moving is M(system)=M(total masses of particles)(sum)


Homework Equations





The Attempt at a Solution



of course no , but these particles isn't photons or electrons my doctor didnt exacly told me what are they so how can i proove the answer is no PLEASE GIVE ME HINTS
 
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What is the rest of the question?
 
this is the question >>
 
If you think the answer is no, then you can pick whatever particle type you want and answer to show the statement is wrong. You just want a counterexample. Photons are a good choice.
 
Last edited:
thank you, you really helped me how to think about the problem...
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

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Thread 'Struggle to understand the concept of the question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
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