Sometimes in Physics one builds a toy model to study some more complicated phenomenon. One example would be the Gross-Neveu model and its relation to QCD.
One considers two equal masses connected by a massless rod. The lenght of the rod isn't fixed, but varies periodically with time so that the masses start together, get apart at a maximum distance, and get back together.
One finds that in that case, depending on how this internal movement is performed, the two massess have their fall accelerated or deaccelerated.
Now, I was given this to work with. I've questioned my advisor: what is the physical motivation behind it? His answer was: "because theoretical physics is this - we imagine one exercise and solve it, there has no physical motivation for it, it is because we want to compute things".
I've insisted, but he said he had no idea what this system could actually represent.
I don't know, but I don't like much this approach. It seems like math: we want to compute things, so we take one exercise out of our heads and do it. I believe that when we set out to research something there should be physics motivation for it. Why this system is important? Is it an approximation for something more complicated that needs understanding? Does it shed light on the understanding of some fundamental physics concept? These things.
So the question here is: this particular example, in the way I've described, is it in the end, some simplification to some real system that occurs in nature? Does it have some real physical relevance to be studied, or is it just one exercise to compute things really?
I've read the answer on this question of mine suggesting that it is somehow related to the so-called EMRIS (extreme mass-ratio inspirals). I've asked to my advisor about this, but he doesn't even know what is an EMRI, so he didn't know if it is related somehow.