Portal [Interesting Physics]

[Reincarnate]

Re: Portal [Interesting Physics]

i can see it now

I WANT TO TRAVEL TO JAMAICA BUT THEY WON'T LET ME THROUGH THE PORTAL

"It's because you're a fat fuck, sir"

[Reincarnate]

Re: Portal [Interesting Physics]

*question 2,
Your ass is getting dropped in acid, if you're moving at a fraction of c in the same direction as one of those light beams, then the forward traveling light beam will reach the portal slower than the one firing towards the rear.

According to the guy on the station

But what about according to the guy on the train?

[darkshark]

Re: Portal [Interesting Physics]

Doesn't matter what the guy on the train thinks, because his friend has melted.

[Reincarnate]

Re: Portal [Interesting Physics]

Speed of light is same for all observers

[darkshark]

Re: Portal [Interesting Physics]

The fact that portals pass kinetic energy through them still leads me to believe they beams would reach at different times, regardless of person#2's relative observation.

Seems like having an object jump from a stationary portal to one that was placed on an object going near the speed of light would be impossible/incredibly destructive.

[leonid]

Re: Portal [Interesting Physics]

Quickly drew this. Can anyone answer to this with explanations?

[Reincarnate]

Re: Portal [Interesting Physics]

sure -- but as you pull that up, I think you'd have to squat so more of you could fit under the table

Trying to stand up straight and then pull on that panel would make you feel the force from the ground working against you

[Reincarnate]

Re: Portal [Interesting Physics]

darkshark: Actually you'd notice no difference between each portal. You could enter back and forth between each portal freely and move between the ship and the station and interact just fine.

The trippy part is that this is actually a basic time travel device

[Oni-Paranoia]

Re: Portal [Interesting Physics]

sure -- but as you pull that up, I think you'd have to squat so more of you could fit under the table

Trying to stand up straight and then pull on that panel would make you feel the force from the ground working against you

So in this case, would your body automatically drop to make room or would you just be in pain until some bones snapped?

[Reincarnate]

Re: Portal [Interesting Physics]

So in this case, would your body automatically drop to make room or would you just be in pain until some bones snapped?

I think it'd be more obvious to look at it this way

[LongGone]

Re: Portal [Interesting Physics]

Quickly drew this. Can anyone answer to this with explanations?

This is probably analogous to: if you were sitting in a canoe and trying the same thing. You can "lift" the canoe higher up your waist but you'd have to squat your legs to fit in the space

[Reincarnate]

Re: Portal [Interesting Physics]

You can't push up on that stick because it's hard-connected to the panel. I don't think you'd be able to "make the platform float" (above the table) if that's what leonid's getting at.

[LongGone]

Re: Portal [Interesting Physics]

Imagine if the panel and bottom portal are right on top of each other

We will have

O
/|\
/\

If you want to make the panel float, i.e.

O
/|\

___
/\

there is nothing holding up the top panel and its "levitating", it will just fall/drop together with your upper body to the table

If you try to "lift" the panel with your upper arms, you will just feel a reaction force to your legs

@qqwref: Your upper body might be exerting an upward force on the panel, but nothing is keeping both your body and the panel suspended in mid air

[qqwref]

Re: Portal [Interesting Physics]

You actually can lift the portal in a way that its location relative to your head doesn't change. When you pull up on the portal, you're actually exerting an upward force on it, so you can hold it in the air, just like how you can hold a hula hoop around your body. Note that relative to your lower body and the ground, your body isn't actually moving, so there's no bootstrap problem here. However, unless you move your legs/torso up or down, the amount of you coming out of the portal should be unchanged. I'm really not sure whether you would have to provide enough force to also lift your upper body, though.

If this is true, and you continually apply enough force to lift it, you could make the upper portal travel up forever. Wouldn't THAT be crazy.

[Reincarnate]

Re: Portal [Interesting Physics]

Say the table is belt-high and we don't want our belt to go anywhere above or below the portal linkage. If we want to lift that panel, I don't think we could do it. Imagine that you just held onto the panel as someone kicked out the table from underneath. Just because you're holding onto the panel doesn't mean you'll float -- your upper torso and the panel will just fall.

By putting an upward force on the panel, our belt would sink below the portal line. If we want to keep the belt constant, then it'd be impossible to pull up on the panel and have it float.

It's like asking why we can't lift ourselves up off the ground when it's so easy to do the same to someone else.