Suppose we could somehow create a box - say 1 foot cubed - and line it with material that's both perfectly reflective and perfectly insulating so that it absorbs no heat. There would have to be one flaw in its design, of course - some sort of opening would be needed to permit the introduction of light into the chamber.If that opening could somehow be made one-way so that all light to enter the chamber was forced to stay there, what would happen as you introduced a steady stream of more light into the chamber?To address the realism of such a thing, suppose the box is formed by intense force-fields, since no matter exists (that we are aware of) that would be capable of having such properties, but in theory it -might- be doable with fields if one had enough energy.Would the input light beam eventually begin bouncing back out at some point, reflected by photons already crowded at the entrans point? Or since the light has no mass, would the energy just keep building up forever?
The train won't move. It has a safety device which ensures that it can't start unless all the doors are closed. If a door jams for any reason, a warning light will show and the train can't start until the door is fixed. In the days when trains had slam doors, this was one of the duties of the guard. The train could not start until all the doors were securely shut, and it was part of the guard's duty to make sure they were before giving 'right away'.
Me and my roommate like to wrap up in a blanket and set the electric heater in the fake fireplace and pretend.
You can see the door edge is rubber. This is a sheet of rubber folded over. This protects a spring which runs top to bottom. Inside the spring is another spring. If the springs touch, electricity flows. This will reopen the door. This is 1920, when airplanes had two wings and they had just invented radio.
Depends on the train. Newer models generally have sensors that stop that doors closing when something is blocking it and the train will generally wait. Older models you need brute force to open, so then you'd be unlucky, but you should be fine just pushing through.
