Checking the Lorentz transformation

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SUMMARY

The discussion focuses on the Lorentz transformation and the calculation of proper time for two moving observers, A and B, with respect to a third observer, C. The proper time for A is derived as ##t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}##, which differs from the initial calculation of ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}##. The confusion arises from the relativity of simultaneity, as the time dilation formulas used for B and C do not correspond correctly when combined. The mentor suggests considering the motion of B in the opposite direction to clarify the relationship between the frames.

PREREQUISITES
  • Understanding of Lorentz transformations in special relativity
  • Familiarity with the concept of proper time
  • Knowledge of relativistic velocity addition
  • Basic grasp of simultaneity in different reference frames
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  • Study the derivation of the Lorentz transformation equations
  • Learn about the implications of simultaneity in special relativity
  • Explore examples of relativistic velocity addition
  • Investigate the concept of time dilation in different inertial frames
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Students of physics, particularly those studying special relativity, as well as educators and anyone interested in the mathematical foundations of relativistic motion.

QipshaqUli
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Homework Statement
This seemed at first glance very easy. But there appeared some confusion.

A is moving to the right with velocity v with respect to B. The proper time for A is ##t_a=t_b\sqrt{1-v^2/c^2}##. And B is moving to the right with velocity u with respect to C. Proper time for B ##t_b=t_c\sqrt{1-u^2/c^2}##. ##t_a## can be found by ##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}## then. Futher, by using the law of addition of relativistic velocities one can find the relative velocity of A with respect to C: ##w=\frac{u+v}{1+\frac{uv}{c^2}}##. And defining proper time for A by ##w## I found ##t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}## which is different from previous one.
Relevant Equations
$$t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}$$
Homework Statement: This seemed at first glance very easy. But there appeared some confusion.

A is moving to the right with velocity v with respect to B. The proper time for A is ##t_a=t_b\sqrt{1-v^2/c^2}##. And B is moving to the right with velocity u with respect to C. Proper time for B ##t_b=t_c\sqrt{1-u^2/c^2}##. ##t_a## can be found by ##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}## then. Futher, by using the law of addition of relativistic velocities one can find the relative velocity of A with respect to C: ##w=\frac{u+v}{1+\frac{uv}{c^2}}##. And defining proper time for A by ##w## I found ##t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}## which is different from previous one.
Homework Equations: $$t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}$$

##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}##

[Note from mentor: please see https://www.physicsforums.com/help/latexhelp/ for the proper delimiters for LaTeX code on this forum. I have edited your post accordingly, in order to make your equations properly visible.]
 
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You have a problem with the relativity of simultaneity. When you use the time dilation formula for B relative to A you are using the simultaneity of A. Similarly, when you use the time dilation formula for C relative to B you are using the simultaneity in the rest frame of B. Thus, the combination will not correspond to the time dilation of C relative to A, which exclusively is based on simultaneity as defined by A.
 
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QipshaqUli said:
Homework Statement: This seemed at first glance very easy. But there appeared some confusion.

A is moving to the right with velocity v with respect to B. The proper time for A is ##t_a=t_b\sqrt{1-v^2/c^2}##. And B is moving to the right with velocity u with respect to C. Proper time for B ##t_b=t_c\sqrt{1-u^2/c^2}##. ##t_a## can be found by ##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}## then. Futher, by using the law of addition of relativistic velocities one can find the relative velocity of A with respect to C: ##w=\frac{u+v}{1+\frac{uv}{c^2}}##. And defining proper time for A by ##w## I found ##t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}## which is different from previous one.
Homework Equations: $$t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}$$

Homework Statement: This seemed at first glance very easy. But there appeared some confusion.

A is moving to the right with velocity v with respect to B. The proper time for A is ##t_a=t_b\sqrt{1-v^2/c^2}##. And B is moving to the right with velocity u with respect to C. Proper time for B ##t_b=t_c\sqrt{1-u^2/c^2}##. ##t_a## can be found by ##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}## then. Futher, by using the law of addition of relativistic velocities one can find the relative velocity of A with respect to C: ##w=\frac{u+v}{1+\frac{uv}{c^2}}##. And defining proper time for A by ##w## I found ##t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}## which is different from previous one.
Homework Equations: $$t_a=t_c\frac{\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}}{1+\frac{uv}{c^2}}$$

##t_c## then: ##t_a=t_c\sqrt{1-u^2/c^2}\sqrt{1-v^2/c^2}##

[Note from mentor: please see https://www.physicsforums.com/help/latexhelp/ for the proper delimiters for LaTeX code on this forum. I have edited your post accordingly, in order to make your equations properly visible.]
Instead, why not have ##B## moving to the left relative to ##C##? The same formulas apply, but now frame ##A## and ##C## are the same frame, yet you have their clocks time dilated relative to each other.
 

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