Special relativity of a light source moving downstream

Click For Summary
SUMMARY

The discussion focuses on the relativistic effects of a light source moving downstream in a flowing medium, specifically water. The speed of light in water, denoted as Cw, is affected by the water's flow speed, v. The key equations for solving the problem involve the relativistic velocity addition formula, which is essential for determining the speed of light signals in both downstream and upstream directions. The participants emphasize the need to understand how velocities combine in a relativistic context to answer the posed questions accurately.

PREREQUISITES
  • Understanding of special relativity principles
  • Familiarity with the relativistic velocity addition formula
  • Knowledge of light propagation in different media, specifically water
  • Basic algebra and manipulation of equations
NEXT STEPS
  • Study the relativistic velocity addition formula in detail
  • Learn about the speed of light in various media, including water
  • Explore the implications of special relativity on signal propagation
  • Review examples of light behavior in moving reference frames
USEFUL FOR

Students of physics, particularly those studying special relativity, educators teaching advanced mechanics, and anyone interested in the behavior of light in moving media.

matt_crouch
Messages
157
Reaction score
1

Homework Statement



Let Cw be the speed of light through water at rest. Water is now flowing at speed v parallel to the x-axis according to one observer, and there is also a light source moving with the water at speed v

1) what is the speed at which the light source sends light signals in the downstream direction?
2) what is the speed at which the light source sends light signals in the upstream direction
3) What happens for the upstream light signal, if v<cw?

a. the signal propagates in the positive x direction
b.the signal propagates in the negative x direction
c the signal propagates at zero speed


Homework Equations





The Attempt at a Solution



i don't really know where to start. I was going to use the equation

x=(gamma)(x'-vt')
but since we don't have the time
im not really sure thanks in advance
 
Physics news on Phys.org
anyone?
 
Hint: How do velocities add relativistically?
 

Similar threads

(Introductory SR) Light sent from a spaceship received by Earth
  • · Replies 6 ·
Replies
6
Views
2K
Special relativity and Lorentz Transformation Exercise
  • · Replies 35 ·
2
Replies
35
Views
5K
Inside glass, can I apply relativity of speed for light?
  • · Replies 4 ·
Replies
4
Views
1K
What angle should a swimmer aim to land directly across the starting position?
  • · Replies 6 ·
Replies
6
Views
2K
Explain how postulates are synthesized into Special Relativity?
  • · Replies 4 ·
Replies
4
Views
2K
Light beam fired in a moving train (relativity)
  • · Replies 23 ·
Replies
23
Views
3K
Length of a Wave Train in Special Relativity
  • · Replies 13 ·
Replies
13
Views
2K
Special Relativity, light down a rocket
  • · Replies 64 ·
3
Replies
64
Views
7K
Special Relativity quick problem
  • · Replies 7 ·
Replies
7
Views
2K
High School Why is the constant speed of light so unique?
  • · Replies 19 ·
Replies
19
Views
2K