Are we allowed to ask questions that pertain to the application of physics on this site? For instance:

What are the advantages and disadvantages of a Bowstring Truss Bridge?

Or is there a different Stack Exchange Site for more engineering-oriented questions?

  • $\begingroup$ IMO, such questions don't need any Physics at all..! Googling (easy or hard depending on the parameter) would provide lots of results for that. I don't think such questions are constructive or show some research effort..! $\endgroup$ Commented May 22, 2013 at 13:14
  • $\begingroup$ By the way, any question that asks for the advantages and disadvantages of something is kind of unfocused. I bet you have a better way to ask this. Something like "I have to span a chasm of such-and-such shape and size, how can I tell if a bowstring truss bridge would work?" That would probably be an engineering question (i.e. not for this site), but it's a much better engineering question. $\endgroup$
    – David Z
    Commented May 22, 2013 at 18:06
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    $\begingroup$ Side note: When I hear "applied physics," I generally think of optics benches, vapor deposition, carbon nanotubes, and microfluidics. Mechanical engineering, though it may be an application of certain physics ideas, isn't quite "applied physics" in the usual sense of the term. $\endgroup$
    – user10851
    Commented May 23, 2013 at 0:07

1 Answer 1


At a minimum the question must reduce to physics. That is, when striped of context it must be answerable in terms of physics.

That implies that there are a lot of engineering questions which probably should not be on physics.se. Some examples of these would be

  • Questions about regulatory issues. Legality and limits of various parameters.
  • Questions about cost or cost/other-metric issues.
  • Questions about engineering tradeoffs, as these necessarily involve decisions beyond physics.

That does leave room for some engineering/design questions. Strength to weight ratios, buckling limits, maximum deflection and so on. However, such questions have generally received little attention in the past. Most of our users have had limited exposure to the complexities of real-world analysis in favor of deeper understanding of microscopic physics.

That is to say most of us are physicists rather than engineers and though we share a lot of common preparation there is a big difference. Heck, there is a big difference even between the real-world preparation of you garden variety experimenter and a bog-standard theorist and the engineers and machinists I work with are always careful--when they first meet me to--to probe how much I know about the real world because they've met enough physicist who are simply dumb about real-world stuff to be wary.

  • $\begingroup$ Thanks for this nice answer and the funny kind of humor, the last paragraph makes me chuckle :-D $\endgroup$
    – Dilaton
    Commented May 22, 2013 at 15:54
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    $\begingroup$ So questions pertaining to my research in materials science would be on-topic? Or would this be too much 'engineering'? To give more detail I'm currently looking at distributions of grain boundary planes in severely deformed Mg alloys. $\endgroup$ Commented May 23, 2013 at 14:14
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    $\begingroup$ @user2307487 Sounds physicy enough to me. Mind you, I don't know how much help you'll get on a specialized topic like that but it can't hurt to ask. $\endgroup$ Commented May 23, 2013 at 15:08

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