Rearranging equation - Relativistic doppler

In summary, to find the velocity, v, of the hydra cluster, which is 900 Mpc away, we can use the equation 487.5 = 396.8 SQRT((1+v/c)/(1-v/c)). To solve for v, we can divide both sides by 396.8, square both sides, multiply both sides by (1-v/c), simplify the left side, and then factor out v and divide by the coefficient of v.
  • #1
roberto85
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Homework Statement


The hydra cluster is 900 Mpc (3x10^9 light years) away. Calcium atoms emit a spectral line of wavelength 396.8 nm. This line is observed at 487.5 nm. The velocity of the cluster, v, is given by ([tex]\lambda[/tex] =c/f)

487.5 = 396.8 SQRT((1+v/c)/(1-v/c))

How do i find v please?


Homework Equations





The Attempt at a Solution

I need to rearrange and this example says take v/c to one side and solve but i don't know how. Well i have taken the numbers to one side, squared them and left with (1+v/c)/(1-v/c) on the other side, how do i find v? Thanks
 
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  • #2
  1. Divide both sides by 396.8.
  2. Square both sides.
  3. Multiply both sides by (1 - v/c).
  4. Carry out the multiplication on the left side.
  5. Get all terms involving v on one side.
  6. Factor v out.
  7. Divide both sides by the coefficient of v.
That should pretty much do it
 
  • #3
Thanks :)
 

FAQ: Rearranging equation - Relativistic doppler

1. How do I rearrange the relativistic doppler equation to solve for the observer's velocity?

To rearrange the relativistic doppler equation, first isolate the observer's velocity term by moving all other terms to the other side of the equation. Then, take the inverse of the cosine function to solve for the observer's velocity.

2. Can the relativistic doppler equation be used for objects moving at any speed?

Yes, the relativistic doppler equation can be used for objects moving at any speed, as long as the relative velocity between the observer and the object is known.

3. What is the difference between the relativistic doppler equation and the classical doppler equation?

The classical doppler equation only takes into account the relative velocity between the observer and the object, while the relativistic doppler equation also considers the effects of time dilation and length contraction due to the object's high speed.

4. How does the relativistic doppler effect differ from the classical doppler effect?

The relativistic doppler effect takes into account the effects of time dilation and length contraction, which can cause a greater shift in frequency and wavelength compared to the classical doppler effect. Additionally, the relativistic doppler effect is applicable to objects moving at speeds close to the speed of light.

5. Is the relativistic doppler equation used in any real-world applications?

Yes, the relativistic doppler equation is used in various fields such as astronomy and physics to calculate the observed frequencies and wavelengths of objects moving at high speeds, such as stars and galaxies. It is also used in applications such as radar and sonar systems.

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