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Thread: Real World Physics In A Game Questions.

  1. #1
    Join Date
    Jul 2006
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    Real World Physics In A Game Questions.

    Playing a blended game and two of my players who seem to be the perennial side plot in most of our games since the 70's found the "good treasure" of the day and nobody realized it at first as it appeared to be simply a pair of Apollo Era space suits.

    On the contrary, these two suits won't be built yet for another 2,000 years or so. (They were the first objects intentionally sent back in time.) A pair of common shipsuits from the fabulous Vega Shipyards.

    As Vega has no gas giants to clean up the local leftovers of stellar formation, part of the standard for EVA suits there is the ability to withstand the impact of a one gram lump of nickel/iron moving at 10% c!

    Now where the argument comes in is one of the suit owners found himself on the wrong end of an argument with an M1 Abrams main battle tank and caught a main battery round at close range, an inch north of the sternum and about 10 meters passed sabot separation.

    *I* had the suit and occupant withstand the impact. The suit went instantly rigid, internal inertia dampeners miniaturized from space fighter designs kicked in, and the wearer saw the world flipping passed his visor until he was buried in the face of a sand dune a quarter mile down range.

    So some players don't agree that a fantasy fabric able to withstand a gram of metal, moving at ten percent of the speed of light, would be proof against a 120mm DU penetrator at max speed.

    If I'm off base here, let me know.

    Question 2!

    Same game, hours later.

    Somebody didn't hear my "Are you sure?" reply before trying to use a salvaged defense field in an off label manner. (As this deed was done as we were close to wrapping up, the consequences have yet to be brewed up.)

    Picture a mountainous region with broad valleys that has rivers near flood stage, is overcast, and with a weather front moving in.

    Guy with defense field wants it to rain more, so the rivers cut off a city from help. He uses various Engineering rolls to soft focus and broad cast the energy absorbing field and uses it at full power, over a domed area ten miles across.

    As far as the whole scheme went he never mentioned adjusting the power settings once, so I *concluded* his device was at full power. And he let loose with a three second pulse, as to not over do it.

    Me: "Good job, it worked, here's your experience points so far. Oh, you do know this device absorbs and stores ten megatons, (4.184e+16 joules), of energy a second, right?"

    And that's when he and the more critical thinkers in the group furrowed their eyebrows.

    Him: "I don't turn it up that high!"

    Me "Too late, I rolled and even gave you EPs already."

    So in your learned opinions, where on the scale of "heavy snowfall to atmospheric collapse" would this error fall?
    Time wasted having fun is not time wasted - Lennon
    (John, not the other one.)

  2. #2
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    I never introduce inertia dampeners to my sci-fi settings because they are so tricky. If they take away the inertia of an incoming item, that item strikes the target and falls to the ground. If it takes away the inertia of the target too, the target's motion stops dead. How do they "start back up" - like the heart and things that need to move? If the heart restarts on it's own after a moment, what about the impactor? There there is the trick of falling and striking the ground. What happens? Does the dampener stop the item they hit or the falling body? Heart problems abound.

    Usually, I meta that sort of thing. A space clearly meant for a pilot's chair, but no chair. Twisted debris leading to a large hole in the wall highlights the missing components. Humorous, yes. Science not a drop.

    I am not sure about the second thing. That is about 10 megatons of work, so I don't think you'd want to stand next to it. Maybe horrible downward winds, rain, hail and snow in a 1 km radius? Splat!
    Solfe

  3. #3
    Join Date
    Sep 2006
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    458
    Well, if I did this BoE calculation correctly . . .

    Kinetic Energy of a M829A1 APFSDS, (penetrator itself is 4.6 kg) is 5.71 Megajoules.
    Kinetic Energy of 1 gram at .1c is 449,377.59 Megajoules (ignoring relativistic issues that probably aren't significant to the comparison).

    I'm sure there are other factors that could be taken into account but the difference in E(k) is so big I can't see how the tank round would be cause for any worry against a suit that can withstand 1 gram at .1c.

  4. #4
    Join Date
    Jul 2006
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    Wow.

    Thank you Darrel.

    I feel better now.

    Solfe, it's story telling time, not class time. I have no problem overlooking it if it makes the story flow along, (AKA willful suspension of disbelief), if it's not too glaring an omission or a complete non-sequitur*.

    *Like the entire last twenty or so minutes the latest version of 3:10 to Yuma, with reality deviations greater than Level Two sprinkled throughout. Saw it last night for the first time. Had to double check the ending and then check to see if it was actually the uncut version and not suffering some local editor's shenanigans. Nope. The director just doesn't know how to tell a story. Or at least a Western.
    Time wasted having fun is not time wasted - Lennon
    (John, not the other one.)

  5. #5
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    Feb 2003
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    Depew, NY
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    I could totally picture a suit with some sort of dampening, but it would proactively flair outwards to intercept an incoming projectile. That would be cool.

    I have a sci-fi story coming out of game 'verse where suits have automatic guns that can knock out incoming grenades and mortar rounds.
    Solfe

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