Ethics of the mention of Nazi weaponry for a computational physics task
German citizen here. My feeling is that your example is not at all outrageous or morally problematic per se; but it might lead to some raised eyebrows in the given setting (a German university) and for quite understandable reasons.

You use a German WW II weapon simply to illustrate some computational problem. That is, you don't make any evaluative statement about nazism, German WW II aggression or even warfare and weapons in general. Neither is your problem about making weapons more effective, which could then be seen as an implicit value judgement.

It is also, fortunately, no longer "taboo" to discuss the nazi past. German political culture has overcome the lead-heavy immediate post-war period, in which the memory of the atrocities that Germans had committed was actively repressed together with everything that reminded of them. To be sure, there is a (perhaps large) minority that prefers to rationalize, relativize or even idealize the nazi regime and its crimes. Some of these guys have a strange fascination for WW II memorabilia and nazi paraphernalia. Here it can be hard to draw the line between hobby historians and hobby revisionists.

So as your student I would wonder: Of all the examples that you could have chosen, why this particular one? If the course was about military history or WW II, the choice of example would make immediate sense. But since it isn't, your example seems quite arbitrary. (Wouldn't other projectiles or objects have similar physical properties?) This would probably lead me to conclude that the example is "just and example", but I couldn't quite help to speculate a bit about your motivation and perhaps your historical-political attitude. Less so, however, if you are not a German.