08-06-2015, 06:18 AM | #11 | |
GURPS FAQ Keeper
Join Date: Mar 2006
Location: Kyïv, Ukraine
|
Re: Reentry with Flight/TK
Quote:
Of course, this is an ugly answer to a question about painfully binary states, describing a phenomenon that is not exactly binary IRL. |
|
08-06-2015, 08:23 AM | #12 |
Join Date: Sep 2007
|
Re: Reentry with Flight/TK
Any character with enough TK to hold themselves off the ground could slow themselves in orbit, while maintaining altitude, and then lower straight down. That just requires devoting more of your "thrust" to maintaining altitude rather than deceleration as you slow -- pulling at a varying angle, that is. Chemical rockets don't do that because it would take too much fuel; the heat shield for reentry weighs less.
The conventional definition for "space" is 100 km. This is about the altitude of the top of the mesosphere. I think the USAF still sticks to 50 miles. As you say, the height for maintaining an orbit without propulsion is a bit higher. If you want to take someone "out to the black" -- visually, that is, so the sky looks black -- that's around 100 miles / 160 km. |
08-07-2015, 12:06 AM | #13 |
Join Date: Jan 2015
Location: UK
|
Re: Reentry with Flight/TK
I remember Kromm saying that for TK, an objects frame of reference is itself. IN the example he gave, if you drove past a resting (with reference to the planet's surface) object in a car going Move 40 and your TK ST was 10, you could still only accelerate that object to Move 10, in any direction, including the direction your car was going. Conversely, if you were "standing still" (see above) and an object were to move through your TK range with Move 40, you could decelerate it to Move 30 (still assuming TK ST 10) or accelerate it sideways with Move 10, but not accelerate it further in the direction it's already going in. The RAW say that TK is capable of short bursts of force that enables the character to "throw" things at higher speeds and beyond his range, but neither the RAW nor Kromm were any more specific than that, other that your TK ST still being the deciding factor.
This is actually a problem with TK I've stumbled on before. For any consideration that involves actual physics (as far as that makes sense for obviously supernatural powers), you'd need the acceleration you can apply to a given mass. At least that's what my rather limited memory of high school physics tells me. TK ST gives us the mass, but only the speed (about 2.1 meters/second (1.8 meters tall person lifting an object overhead in one second, as described for Basic Lift (B15))). I assume that is not even the top speed, since the distance of 2.1 meters and the time of one second also includes acceleration from zero and deceleration back to zero. Hm, now that I think of it... Maybe one can work something out with the different Encumberance levels. Don't know if my Physics Fu is strong enough for that, assuming that idea isn't totally useless altogether. Will try to apply some brain to it this evening, gotta make my Job Roll. Last edited by CeeDub; 08-07-2015 at 12:08 AM. Reason: typos |
08-07-2015, 12:12 AM | #14 | |
GURPS FAQ Keeper
Join Date: Mar 2006
Location: Kyïv, Ukraine
|
Re: Reentry with Flight/TK
Quote:
For uncontrolled velocities (when you accelerate the object as you release it in the desired direction), use the Throwing rules, just like you do when providing a burst of acceleration to a dart with your hand (that happens to also be in excess of your Move!). |
|
08-07-2015, 01:50 AM | #15 | |
Join Date: Jan 2015
Location: UK
|
Re: Reentry with Flight/TK
Quote:
That is, of course, if you really meant that the acceleration (not the speed) for subsequent turns is TK Move. Or unless I misuderstood you really badly. |
|
08-07-2015, 02:10 AM | #16 | |||
GURPS FAQ Keeper
Join Date: Mar 2006
Location: Kyïv, Ukraine
|
Re: Reentry with Flight/TK
Quote:
"You can move any object you have strength enough to lift, at a Move equal to your TK level, modified as usual for encum- brance level (see Encumbrance and Move, p. 17)" You can only move objects relative to the relevant reference frame at up to TK y/s, but you can accelerate them up to this velocity quite fast. If your reference frame is yourself, you cannot accelerate yourself because you are always at rest relative to yourself. So when moving yourself, you have to deal with some other reference frame than yourself. Quote:
Quote:
High acceleration does not automatically assume unlimited velocity. |
|||
08-07-2015, 04:59 AM | #17 | |
Join Date: Jan 2015
Location: UK
|
Re: Reentry with Flight/TK
Quote:
The "problem" is that it uses an inconsistent frame of reference. If I levitate on a moving train, I float through the passenger compartment at TK Move in any direction instead of taking collision damage from instantly crashing into the rear compartment wall (I move at TK Move, the train moves a lot faster). If I move an object outside the train (resting at Move 0), the object's position on the planet's surface is its frame of reference, meaning I can cause a one-time change in speed of TK Move in any direction and maintain that for as long as I'm in range. The same applies if I move myself. The thing is that physics don't actually work that way. (The obvious answer is, of course "Duh! You can't really move stuff with your mind, it's a game of make-believe!") As far as I understand, you'd apply a certain amount of Force (which is mass * acceleration) to an object, and its mass then determines its acceleration. If you were to continue to apply the same amount of Force, acceleration would continue at the same rate (if it weren't for gravity and air resistance). Frex, you should be able to move (and accelerate) an object faster horizontally than straight up. The RAW partially reflect this in that you can shove or slighty shift an object of higher mass than you could lift with two hands. In the vast majority of uses in the game, the RAW are totally sufficient and balanced as game mechanics. Only when you try to reenter a planet's atmosphere with TK (or try to use TK to push yourself along on a bicycle, which is how I got to thinking about this), the mechanics stop making sense. The easiest solution is to have the GM make a judgement call, taking into consideration the campaign's intended realism and/or how much having PCs burning up in the atmosphere moves the plot along. On the other hand, I think it'd be really interesting and neat to try and work this out. Unfortunately, my Physics Fu is weak and brings shame on my family. |
|
Tags |
basic set, flight, telekinesis |
|
|