sidharath Posted April 2, 2014 Share Posted April 2, 2014 suppose in thought experiment there are two cabins , one cabin is plaed at rest in gravitational field while the second cabin is accelarated in direction from bottom to ceiling with acceleration g.. In both the cabins elastic string is attached to he ceiling.To the ewn of the spring in both the cabins certain mass is attached..The spring will be stretched in both the cabins but with difference that the extent of stretching will not change with time in the cabin placed in gravitational field while the extent of stretching will go on increasig with time in the accelerated cabin . It is so because the spring is attached to cabin hence its velocity and the velocity of the mass attached to it will go on increasig with time because cabin is accelewrated..According to special theory of relativity the increase in velocity will increase the mass which will result in more stretching of the accelerated spring. Special theory of relativity is applicable to accelerated frame though with the difference that instantaneous velocity is to be considered.The above observation shows that the two frames are not equivalent but equivalence principle of general relativity states that the two cabins or frames are equivalent . -1 Link to comment Share on other sites More sharing options...
studiot Posted April 2, 2014 Share Posted April 2, 2014 Does an observer in the same intertial frame as the mass and spring observe the mass as increasing? In particular does the spring 'observe' an increase in suspended mass? Link to comment Share on other sites More sharing options...
Spyman Posted April 2, 2014 Share Posted April 2, 2014 A scientist standing inside anyone of the cabins will not be able to measure any difference in the springs, because in his frame of reference the cabin is not moving and thus the mass of the object hanging at the spring don't increase. If the moving cabin has transparent walls so a scientist in a different frame of reference can make the measurements then it is also important to take into consideration all other effects, like for instance that the spring will be subjected to lenght contraction. Link to comment Share on other sites More sharing options...
swansont Posted April 2, 2014 Share Posted April 2, 2014 the velocity of the mass attached to it will go on increasig with time because cabin is accelewrated..According to special theory of relativity the increase in velocity will increase the mass which will result in more stretching of the accelerated spring. Nope. Link to comment Share on other sites More sharing options...
pzkpfw Posted April 3, 2014 Share Posted April 3, 2014 Didn't you already do this topic? http://www.scienceforums.net/topic/73539-general-relativity Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted April 3, 2014 Share Posted April 3, 2014 Does an observer in the same intertial frame as the mass and spring observe the mass as increasing? In particular does the spring 'observe' an increase in suspended mass? Same frame? Link to comment Share on other sites More sharing options...
studiot Posted April 3, 2014 Share Posted April 3, 2014 Same frame? Yes it is the condition for this A scientist standing inside anyone of the cabins will not be able to measure any difference in the springs, because in his frame of reference the cabin is not moving and thus the mass of the object hanging at the spring don't increase. Link to comment Share on other sites More sharing options...
sidharath Posted April 3, 2014 Author Share Posted April 3, 2014 please devote some time to answer the following queries related to the topic 1.there is increase in mass of the accelerated electron in cyclotron and adjustment has to be made for it.., in the case under study mass along with the spring and cabin is accelerated hence there is real extension whether you observe it from inside or outside the cabin 2if one pair of electron and positron moving with very high speed in opposite directions is annihilated while another pair moving slowly in opposite directions is annihilated the frequency of photons liberated in the former case will be more than latter case due to more increase in mass in the former case 3The force formula when the mass is moving with high speed is not equal to mass into acceleration d -1 Link to comment Share on other sites More sharing options...
Strange Posted April 3, 2014 Share Posted April 3, 2014 (edited) please devote some time to answer the following queries related to the topic I'm sure this has been explained to you before: in the frame of reference of the cabin (or of the electron) there is no increase in mass. It is called the theory of relativity for a reason. This is one reason why some people think the concept of relativistic mass should be dropped; it confuses people in this way. 2if one pair of electron and positron moving with very high speed in opposite directions is annihilated while another pair moving slowly in opposite directions is annihilated the frequency of photons liberated in the former case will be more than latter case due to more increase in mass in the former case It depends in what frame of reference you measure the speed, energy and frequency. (These are all observer dependent.) Edited April 3, 2014 by Strange Link to comment Share on other sites More sharing options...
swansont Posted April 3, 2014 Share Posted April 3, 2014 please devote some time to answer the following queries related to the topic 1.there is increase in mass of the accelerated electron in cyclotron and adjustment has to be made for it.., in the case under study mass along with the spring and cabin is accelerated hence there is real extension whether you observe it from inside or outside the cabin 2if one pair of electron and positron moving with very high speed in opposite directions is annihilated while another pair moving slowly in opposite directions is annihilated the frequency of photons liberated in the former case will be more than latter case due to more increase in mass in the former case 3The force formula when the mass is moving with high speed is not equal to mass into acceleration d The relativistic properties of the electron are observed in the cyclotron's frame. Link to comment Share on other sites More sharing options...
Schneibster Posted April 4, 2014 Share Posted April 4, 2014 the extent of stretching will go on increasig with time in the accelerated cabin No. The spring will remain stretched to the same extent in both cabins. Acceleration stretches the spring, not speed. 1 Link to comment Share on other sites More sharing options...
davidivad Posted April 4, 2014 Share Posted April 4, 2014 there's no place like home there's no place like home. i think the issue here is to due with the set-up of the experiment. Link to comment Share on other sites More sharing options...
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