Electrons - Relativistic velocity addition

AI Thread Summary
The discussion centers on calculating the relative speed of two electrons moving at c/2 in perpendicular directions. The initial approach using the Pythagorean theorem for velocity addition is deemed incorrect due to the relativistic speeds involved. Instead, the proper method requires applying the principles of special relativity for accurate results. Participants emphasize the importance of using relativistic velocity addition rather than classical methods. The conversation concludes with a light-hearted exchange about the assignment's progress.
charmedbeauty
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electrons -- Relativistic velocity addition...

Homework Statement



an observer measures the velocity of two electrons, finding one with a speed c/2 in the x direction and the other c/2 in the y direction. what is the relative speed of the two electrons.



Homework Equations





The Attempt at a Solution



Im not sure if this is right it seemed to easy.

but suppose that electron 1 is called b and the other a

then v(b)= √(c2/4+c2/4)
since they are at right angles to each other. is this right?
 
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The velocities are very high, you need to use special relativity here.
 


charmedbeauty said:

Homework Statement



an observer measures the velocity of two electrons, finding one with a speed c/2 in the x direction and the other c/2 in the y direction. what is the relative speed of the two electrons.



Homework Equations





The Attempt at a Solution



Im not sure if this is right it seemed to easy.

but suppose that electron 1 is called b and the other a

then v(b)= √(c2/4+c2/4)
since they are at right angles to each other. is this right?

No. That is a non-relativistic velocity-addition and would give you the right answer for a speeding bullet on Earth but NOT for things traveling at relativistic speeds.

Google relativistic velocity addition
 


voko said:
The velocities are very high, you need to use special relativity here.

phinds said:
No. That is a non-relativistic velocity-addition and would give you the right answer for a speeding bullet on Earth but NOT for things traveling at relativistic speeds.

Google relativistic velocity addition

oh yeah that makes sense ok cool thanks.
 


How did you go with the rest of the assignment =P
 
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