Dr. Courtney said:
Wow! That's tough. In addition to generating interest in the science, you may want to consider bureaucratic and legal challenges if you just show up on a corner downtown and start performing demonstration physics experiments.
You also have a challenge in matching the learning objective of the "lessons" with the interests and abilities of the audience. Street corner audiences will vary widely from one street corner to another.
I've seen chemistry "magic shows" succeed to some degree with a wide range of audiences, but these have tended to be in environments more controlled than street corners.
Great idea, lots of challenges. Let us know how it goes.
I'd start by articulating goals, "take aways", and learning objectives for the audience. Decide if you priority is the bread and butter mechanics, E&M, and thermo that has more obvious applications in engineering, or of you want to give a pitch for more contemporary developments.
You also need to consider whether you want the audience to actually accurately remember any real physics, or if you want to keep it all in the gee whiz zone, where they come away liking physics, but not understanding much better than before. Sad to say, most of those "chemistry magic shows" succeed more at communicating how cool chemistry is without imparting any real scientific knowledge.