plumtreeblossom

From:

Loads of physics in all kinds of areas:

Onstage:

Onstage fighting (already mentioned)

Singing (movement of air across vocal chords tensed to vibrate at different ratios to produce melodic sounds)

Curtains pulled across the stage if it has a proscenium (think of The Somerville Theater).

Use of something like silk stretched across a stage with light aimed at it to create illusions of water (with fans blowing on it across a stage) or fire (with fans blowing it up)

Smoke. If made with dry ice, it can be dangerous because it will suck up all the oxygen, which is why we tend to make smoke with particulate matter instead. Although I suppose that's more chemistry than physics.

Flying. Anytime someone flies onstage, there are all kinds of physics involved (think Peter Pan, Cats, Spider Man & Wicked).

trampolines: Think Cirque de Soleil where they slide back part of the stage and below are trampolines!

Backstage:

Scenery on pulleys in fly space above a given theatre

Lights being set at angles on bars so that the weight of the light is parallel to the bar (so where the grip happens has to have a specific tightness or it will slide due to the exertion of gravity) and it has to be balanced with the overall weight balanced on the piece of pipe hanging by chains from the ceiling.

Rolling sets, of course. Both in the case of set-pieces rolling across the stage and in the case of pieces of the stage rolling, coming up from the floor..etc.

Raking a stage is simply building a false stage over the one you have that is at an angle to the floor with it being about an inch off the ground in the front and about 1 foot to many feet up in the back (depending on the play). It gives the audience the opportunity to see more of what's happening upstage.

Illusionary things....painting things in perspective to make them lok closer/further away.