(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The equations of motion are:

[tex] \frac{d^2 x^\mu}{d\tau ^2} = 0 [/tex]

Write down the tra jectory that’s the most general solution to them. What are the conditions

on your solution if the particle is:

(a) Massive?

(b) Massless?

3. The attempt at a solution

I am not too sure what is meant by write down, but judging from equation I can assume that the path is straight worldlinefor a massive particle in spacetime, since there is no four-force acting on it. What my main problem is the massless particle, as it is obvious that the acceleration is 0 from the fact that massless particles should always travel at c. Any idea what is meant by that. I am really sorry for asking, but the prof is the kind of person who states that everything is supposed to be from kindergarten.. string theorists don't you love them.

Cheers,

Biest

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# Homework Help: Trajectories in spacetime

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