• Zombiepirate@lemmy.worldEnglish
    452·
    25 days ago

    Ok, but hear me out:

    If you accelerate something into a freefall orbit, then it stands to reason that the projectile would deal falling damage (equal and opposite force, you know) which maxes out at 20 d6.

    • traceur402@lemmy.blahaj.zone
      44·
      25 days ago

      If a character has 121hp or more they’re able to jump from a space station onto earth with like a super hero landing??

      • milkisklim@lemmy.world
        22·
        25 days ago

        In 5e yes. I think the theory is once you hit terminal velocity, you aren’t going to get any more damage from a longer fall.

        Fun fact, I actually did have a villain do exactly that in a campaign once. The party achieved a secondary win condition during combat and so the BBEG jumped off the top of the space elevator to escape.

        • turdas@suppo.fi
          6·
          24 days ago

          Wouldn’t jumping off the top of a space elevator just put you in orbit? Or, if by top you mean the point where the space elevator anchors to its counterweight, in orbit around the sun.

          • Cethin@lemmy.zipEnglish
            2·
            24 days ago

            OK, you’ve got space elevators wrong, and that’s OK.

            The counter-weight doesn’t orbit the sun. It orbits earth. If it orbited the sun it’d rip the thing apart. It sits somewhere above a geostationary orbit, as a geostationary orbit is where the orbit point is always over the same point on the ground, which would be where your elevator is tethered.

            The station part is somewhere below this. The higher it is the heavier or further out your counter-weight needs to be —and since it’s already impossible around earth no matter what, this needs to be as low as possible.

            Because of this setup, your velocity (while below the geostationary line) is always less than the orbital velocity at that altitude. For example, the ISS orbits the earth 15.5 times a day. Our point on the space elevator cable stays at the exact same position over the ground, so it orbits 0 times. At the same altitude as the ISS you need to be moving the same speed as the ISS or you’ll fall down. It only doesn’t while attached to the cable because it’s being pulled by the counter-weight.

            Basically, stuff dropped off a space elevator falls, unless it’s at geostationary altitude. It needs to be given some extra horizontal speed to stay in orbit.

            • turdas@suppo.fi
              3·
              24 days ago

              The counterweight orbits above escape velocity, pulling the space elevator’s cable taut. If the cable were severed the counterweight would drift off into space into a solar orbit. So if you jump off at the counterweight, you’ll enter solar orbit.

              At geostationary orbit (which could be considered the “top” of the space elevator as that’s where you would normally get off, presumably) the space elevator orbits at exactly orbital velocity, so if you jump off there you end up in orbit. Below that your velocity would be below orbital velocity and you’d fall back to Earth.

              • Cethin@lemmy.zipEnglish
                1·
                23 days ago

                Well, the “top” of the elevator could be anywhere. That’s why I said it needs to be as low as possible, because it’s already physically impossible for Earth. The lower and lighter the station is, the less impossible it is, though it’s impossible even with no station and just a cable.

                Above geostationary orbit isn’t suddenly in solar orbit though. It’s still got quite a ways to go. It could be at escape velocity, but that’s not necessary.

                This is all impossible on Earth anyway though, so if you’re making a story where this is taking place it could be any of these outcomes you want. Whatever works best for the story.

                • turdas@suppo.fi
                  1·
                  23 days ago

                  It’s not “physically impossible” on Earth. The forces involved are great, sure, which means you can’t build it out of any present-day material like steel, but they’re not so great that constructing a space elevator would be physically impossible using non-exotic matter like it would be on, say, the Sun, or possibly even just Jupiter. We already know of materials that could be used to make a space elevator cable on Earth if they were available in sufficient quantities – namely carbon nanotubes.

                  The “top” can’t be anywhere, because not everywhere along the length of the elevator will put released objects in orbit. Turns out on Earth, an object released off of the elevator would reach a stable (but very eccentric) orbit 2/3rds of the way to geostationary orbit – below that, it would fall back to Earth. Conversely escape velocity would be reached at about 53000 km, which is past geostationary orbit but much closer than where the counterweight would be (in most designs?). Objects above escape velocity will by definition escape Earth’s orbit, which most of the time means ending up in a solar orbit.

                  • Cethin@lemmy.zipEnglish
                    1·
                    23 days ago

                    No, it’s physically impossible. Even the most advanced material possible couldn’t hold the strain that would be required for Earth. Technically it’s right on the limit, but that’s ignoring that we have an atmosphere that’s going to exert forces on it too. On Luna it might make sense.

                    The top can be anywhere. It would just require adding force to it at/after release. That’s trivial. We already know how to make rockets, or it could be something that pushes or throws it. Compared to building a space elevator, speeding something up is easy.

      • riwo@lemmy.blahaj.zone
        111·
        25 days ago

        theyd also need something to protect them from the friction and resulting heat of air brushing by at terminal velocity tho, i assume?

        oh no wait, im making it too realistic

        • Afaithfulnihilist@lemmy.dbzer0.com
          141·
          25 days ago

          Terminal velocity for a human is not fast enough to cause air to heat up. You’d probably get frostburn instead.

          • usualsuspect191@lemmy.ca
            18·
            25 days ago

            If you’re jumping from a space station then you’d be traveling at orbital velocity when hitting the atmosphere which is plenty fast enough to generate heat.

          • Kichae@wanderingadventure.party
            4·
            25 days ago

            Heating on reentry is actually due to compressing the air in front of you, not friction. Falling from orbitall height will absolutely cause you to heat up the air in front of you, even as the air paassing you by is doing you no harm.

            Though, if you smash into the atmosphere at orbital speeds, it’s probably going to do you some harm as it tries to force you back down to TV.

          • athatet@lemmy.zip
            2·
            25 days ago

            Hold up. Didn’t some guy drop balls off a roof to show that things fall at the same speed?

            • BreakerSwitch@lemmy.worldEnglish
              10·
              25 days ago

              So, yes and no. Acceleration due to gravity impacts all objects equally. With no air resistance, on earth, everything speeds up at 9.8m/s/s. But, that “no air resistance” is a big asterisk. This is why, say, parachutes work. It’s also how we get terminal velocity. Often misinterpreted as “how fast you’d have to go to die from a fall” it’s actually “how fast you need to go before the drag from your air resistance is a force greater than or equal to gravity”

              • athatet@lemmy.zip
                3·
                25 days ago

                Right. That all makes sense. So the air resistance is what is also causing it to heat up. I still don’t see why a person wouldn’t do that.

                • BreakerSwitch@lemmy.worldEnglish
                  13·
                  25 days ago

                  So, multiple options here. Skydivers regularly hit terminal velocity, as fast as they’ll go in atmosphere, before pulling their chutes. At these speeds, heat from friction isn’t enough to worry about. Once again though, if you’re coming down from space, that “in atmosphere” asterisk goes away. If you’re dropping from a satellite, you’re going at speeds necessary to orbit, and you don’t have anything slowing you down until you hit the atmosphere. Suddenly your terminal velocity is way lower than infinity, and the friction you’re feeling from the atmosphere is INTENSE, rapidly turning that speed into heat

                  • athatet@lemmy.zip
                    2·
                    25 days ago

                    Alight cool. All basically what I figured. Thanks!

            • psud@aussie.zoneEnglish
              4·
              24 days ago

              I recently had this explained to me, terminal velocity is falling versus the force of the air pushing back on you, right? In vacuum you just keep accelerating, in atmosphere the air pushes back against you falling, limiting your speed

              That force follows the rule that force (of air pushing back) is equal to acceleration (9.8m/s/s) times mass

              So different weights fall at different speeds.

              Half of the replies to me when I said what you said were

              Idiot, f=ma

              Or similar

              • athatet@lemmy.zip
                1·
                25 days ago

                Well sure but I don’t think a human is shaped in a way that would really affect this.

                • Bronzebeard@lemmy.zip
                  3·
                  24 days ago

                  Never seen a sky diver? Head down vs belly flop changes their speed

                  • athatet@lemmy.zip
                    11·
                    24 days ago

                    Still won’t stop you from eventually reaching the same speed tho.

        • turdcollector69@lemmy.world
          4·
          24 days ago

          Piss hard so the reaction mass slows you down along with the cloud of expanding piss vapor.

          They call me the yellow comet

      • Archpawn@lemmy.world
        3·
        25 days ago

        No. They’d need a pretty impressive jump height to slow down enough to leave orbit.

    • Jeeve65@ttrpg.network
      153·
      25 days ago

      Applying real world logic to game rules never works out.

      Also, you forget to take into account the weapon’s mass, form, structural integrity, the commoner’s reaction time, probability to fumble, the force of the wind, and probably a few dozen other factors that have an effect in the real world.

      Just don’t. It’s a game.

    • JackbyDev@programming.devEnglish
      5·
      25 days ago

      If you can manage to get someone into freefall I’d allow it. But no, equal opposite forces doesn’t mean you roll dice the same lol. Your sword does not take damage when you attack with it.