looking for some help working out a minor physics problem:
Let us say that a medium-sized (225lb) creature is free-falling from a tremendous height and reaches terminal velocity. As the creature approaches the ground they cast Teleport. They choose, as their destination a point 11 feet from the ground. Since the Teleport spell wouldn’t alter their terminal velocity, they wisely invert their orientation upon completing the teleportation. Now they appear 11 feet off the ground and their velocity propels them upward. So, physics geniuses, if a 225lb person appears 11ft off the ground, traveling upward at terminal velocity, at what height would gravity halt their upward trajectory?
Approximately the same distance as it took for them to reach terminal velocity. There's a wikipedia article that says about 1500ft give or take.
That is 7.5 times the distance the game rules say it takes for a falling humanoid (or a falling anything, really) to reach terminal velocity, if you consider falling damage proportional to speed of fall.
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Also, if the intent is to hit the ground with less speed, by losing some speed by reversing direction, it won't work. If you start out at 11' from the ground, moving upwards at any speed*, by the time you're back falling downwards, and passing 11' again, you'd be moving at the same speed you started with.
*Well, not quite "any" speed, because of air resistance, but close enough, especially since you'd be limited to terminal velocity to begin with.
Why would teleport not alter their velocity? It's *magic*.
Have you ever played the game Portal? If you are going at incredible speeds, the portal doesn't stop those speeds. It's like an open doorway. In my head, it would work the same way here. However, I'm not a math nerd, and know very little about physics. What I do know is that in order for something to slow down, it has to be acted upon by a force. I don't think a teleport spell would be enough of a force to do that.
Why would teleport not alter their velocity? It's *magic*.
Have you ever played the game Portal? If you are going at incredible speeds, the portal doesn't stop those speeds. It's like an open doorway. In my head, it would work the same way here. However, I'm not a math nerd, and know very little about physics. What I do know is that in order for something to slow down, it has to be acted upon by a force. I don't think a teleport spell would be enough of a force to do that.
Time for some mod vs mod magic-science theory debate?!
<tweaks glasses>
As much as I love Portal, the devil's in the details. The wording of the teleport spell is that it transports you, and in my mind if magic moves you, it has overridden your own mundane, physical movement.
Compare with Arcane Gate, which is D&D's own Portal-game portal spell. It's a PHB spell so I don't want to copy too much of the text, but it says 'Any creature or object entering the portal exits from the other portal as if the two were adjacent to each other'. Which implies continued momentum, as if it was an open gateway.
However, to go back to Garrett's original question, and assuming in that actual 'teleport' works as described, an accurate answer will depend on determining how fast the terminal velocity actually is for the creature. It will depend on how aerodynamic the creature is, and at what altitude they're landing. The higher up you are, the thinner the air, and subsequently the faster you fall.
Spells don't do anything they don't say they do, so RAW teleportation spells just change your position; you don't get to change the direction of your velocity.
Even if your DM allows it though, it doesn't make sense to come out straight upwards, as Tonio pointed out. It'd be smarter to come out at a slightly vertical angle (e.g. 15 degrees). The majority of your speed becomes horizontal, which you'll lose gradually by rolling along the ground. Coming out slightly upwards will reduce your horizontal speed a bit without sending you so high that you'll take a lot of fall damage. The optimal angle would depend on how the DM adjudicates the rolling damage.
At which point, you will run out of forward momentum. For a brief moment, you will hang suspended in the air, completed stopped at the top of your parabola.
And then gravity, that cruel mistress, will bring you hurtling right back down. Your ascent will have taken about 5.5 seconds, but your descent will take much longer. You will be falling for ten seconds, which is ample time for you to return to terminal velocity (just in time to hit the ground.)
looking for some help working out a minor physics problem:
Let us say that a medium-sized (225lb) creature is free-falling from a tremendous height and reaches terminal velocity. As the creature approaches the ground they cast Teleport. They choose, as their destination a point 11 feet from the ground. Since the Teleport spell wouldn’t alter their terminal velocity, they wisely invert their orientation upon completing the teleportation. Now they appear 11 feet off the ground and their velocity propels them upward. So, physics geniuses, if a 225lb person appears 11ft off the ground, traveling upward at terminal velocity, at what height would gravity halt their upward trajectory?
Approximately the same distance as it took for them to reach terminal velocity. There's a wikipedia article that says about 1500ft give or take.
"Any society that would give up a little liberty to gain a little security will deserve neither and lose both" -- allegedly Benjamin Franklin
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Also, if the intent is to hit the ground with less speed, by losing some speed by reversing direction, it won't work. If you start out at 11' from the ground, moving upwards at any speed*, by the time you're back falling downwards, and passing 11' again, you'd be moving at the same speed you started with.
*Well, not quite "any" speed, because of air resistance, but close enough, especially since you'd be limited to terminal velocity to begin with.
Why would teleport not alter their velocity? It's *magic*.
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Time for some mod vs mod magic-science theory debate?!
<tweaks glasses>
As much as I love Portal, the devil's in the details. The wording of the teleport spell is that it transports you, and in my mind if magic moves you, it has overridden your own mundane, physical movement.
Compare with Arcane Gate, which is D&D's own Portal-game portal spell. It's a PHB spell so I don't want to copy too much of the text, but it says 'Any creature or object entering the portal exits from the other portal as if the two were adjacent to each other'. Which implies continued momentum, as if it was an open gateway.
However, to go back to Garrett's original question, and assuming in that actual 'teleport' works as described, an accurate answer will depend on determining how fast the terminal velocity actually is for the creature. It will depend on how aerodynamic the creature is, and at what altitude they're landing. The higher up you are, the thinner the air, and subsequently the faster you fall.
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Spells don't do anything they don't say they do, so RAW teleportation spells just change your position; you don't get to change the direction of your velocity.
Even if your DM allows it though, it doesn't make sense to come out straight upwards, as Tonio pointed out. It'd be smarter to come out at a slightly vertical angle (e.g. 15 degrees). The majority of your speed becomes horizontal, which you'll lose gradually by rolling along the ground. Coming out slightly upwards will reduce your horizontal speed a bit without sending you so high that you'll take a lot of fall damage. The optimal angle would depend on how the DM adjudicates the rolling damage.
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You will go straight up about 500 feet.
At which point, you will run out of forward momentum. For a brief moment, you will hang suspended in the air, completed stopped at the top of your parabola.
And then gravity, that cruel mistress, will bring you hurtling right back down. Your ascent will have taken about 5.5 seconds, but your descent will take much longer. You will be falling for ten seconds, which is ample time for you to return to terminal velocity (just in time to hit the ground.)
Here's a look at some of the math:
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