The idea is simple:
Have a "Quality" or "Approved" tag for questions complete with full, quality answers.
A user (a beginner in physics, maybe) a basic question and get answers that (as a whole) would make for a good starting point on the concept. The mod-only tag would designate these questions as complete, high quality and accurate.
Maybe also a public tag to put a question into the attention of mods if the user has asked what s/he believes a question fitting the criteria.
Example: A question about velocity (maybe) and how it differs in Vacuum from on Earth. Why velocity captures the direction beside the speed. And why a force on Earth's surface wouldn't always translate to a tangible acceleration because other factors speed-down the body; so force does actually increase the velocity of a body but not necessarily sustain its current one in all cases akin to what's visible to the layman on Earth.
^That's a pretty basic question and would as an excellent introduction to velocity. Furthermore, since it's so basic, it's unlikely that a similarly phrased question might need different answers than one already asked. A tag to designate these questions would make a very good index (of all questions tagged as such) for basic concepts as explained above.