Re: In search of the perfect Disassembler

Beth wrote: 

If you fired a laser at me - rather than my (meant to be comical) "disco
lights" / "torch" example - then - ouch! - it would burn like buggery...oh
dear, a hole seems to have been burnt straight through my hand

That would depend on the intensity of the laser. The laser in your CDROM drive, for instance, isn't going to burn a hole in anything.

...but you
couldn't knock me over with it, as it doesn't have mass, so doesn't exert
"force"

Sorry, but no. Photons have no rest mass, but they do have mass, because they have energy. The full Einstein equation is:

E**2 = p**2 + m**2

in units where c == 1, where p is momentum and m is rest mass and E is energy. So even when m = 0, there is still momentum and kinetic energy. Since F = dp/dt, when a photon bounces off something its momentum changes and thus it exerts a force.

Note that if photons had no mass, their trajectories could not be bent by gravity, and gravitational lenses would not work, among other things.

"F = ma"; If "m" (mass) is zero, then "F" (force) is zero, no matter how
much "oomph" (a) you put into it...

F = ma can only be used classically, and even then only in a restricted problem domain.

"Star Wars Episode IV" (which is just
"Arthurian legend in disguise", anyway)

Huh? It's based on space operas, on westerns, on Kurasawa movies (the 2 robots are from "The Hidden Fortress"), but I see no resemblance to the Arthurian stories.

--
Thomas M. Sommers -- tms@xxxxxx -- AB2SB

.

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