> Recently in a conceptual physics course, the prof. posed an interesting question concerning relativity. Thought I'd share it.
>
> A few basics of relativity first:
>
> 1)Anyone moving at a constant speed can claim (correctly) to be at rest. In other words, someone driving down a highway at 55mph to an observer on the side of the road can correctly claim that he is not moving at all, and it is the observer who is moving at 55mph.
>
> 2)Fast moving things shrink in the direction of motion by the factor y (actually the greek letter gamma, but it looks kinda like a "y"), which is a function of their speed. Moving clocks also run slow by that same factor.
>
> 3)Simultaneous events according to one observer do not happen at the same time according to another observer in motion relative to the first. According to the second observer, the event at the "rear" (the end furthest away) will occur before the event at the "front."
>
> Anyway, here's the question (modified slightly):
>
> Spider-Boy is the conductor of a train carrying rare and valuable comic books across the country. This state-of-the-art train travels at 80% of the speed of light (240,000 km/sec).
>
> Up ahead is a tunnel that happens to be exactly the same length as the train. On top of the tunnel is Brunnen-G, who hopes to rob the train. He knows that since the train is moving so fast, it will shrink to 3/5 of its normal length.
> He has therefore stationed a giant evil space bug at the front and rear of the tunnel. When the train is completely inside of the tunnel, he will command the bugs to drop simultaneously, thus blocking the train in and allowing him to loot the train of its comic books.
>
> Spider-Boy hears of the plan, but simply laughs it off. He knows that he is at rest (see statment #1) and it is the tunnel that is moving; therefore the tunnel will shrink to 3/5 of its length and there will be no time when the entire
> train is inside the tunnel. The space bugs won't be able to drop, and the comics are safe.
>
> So, what happens? Will the comics make it to the convention safely, or will they become part of Brunnen-G's personal collection?
>
> Bal "no comic books were harmed in the posting of this question" anthalus

The real question is:
1) What sort of convention can afford to hire a state-of-the-art train which travels at 80% of the speed of light just to deliver comic books?
2) Can you imagine anyone who owns such a train allowing Spider-Boy to drive it?
3) Does Balanthalus realise how annoying it is to post such a question when there are people like me reading it, when any question involving physics (conceptual or otherwise) makes me want to curl up and hide under a bed somewhere?

Brunnen-"and if I could tell giant evil space bugs what to do, all my problems would be over"G