What happens, Veeky Forums?

A. Work is defined as the amount of force necessary to move an object a distance of D. Work = Fd = mad

There isn't any mass acting upon the block thus it moves a distance of zero. Once it pops out of the portal, because the portal acts as a massless object (otherwise it would push the block) the force of gravity causes it to descend, and it can't go back into the portal due to the platform preventing it from doing so.

Due to there being zero work done on the object. it descends due to g and the platform being there in the portal's mechanisms, thus A, it descends at an angle.

No work is done on the object, thus it propels at a distance of 0. A IS THE CORRECT ANSWER GWAH

they also must be oriented spatially the same direction

Energy isn't conserved, so you can't conclude that it doesn't move just because no work is performed on it.

If portals existm, you can see both rooms via your own sight and through the protal. Both rooms are in the reference frame. If the portal exists as a tube, then the propelling force is added to the portal's velocity, the velocity of the portal gets added to the acceleration of the portal's movement, meaning it would propel at v + a. If there is no tube, then it's only v of the portal's descension, at which point it stops descending, v becomes 0, thus A, it doesn't accelerate against gravity because a = 0.

Depends on if portals are tubular or not.

If it isn't conserved then v become zero as the portal's descension becomes zero. A

Just look at it from the reference frame of the orange portal. That should make it obvious that the answer is B, unless portals absolutely destroy our current understanding of all physics.

>unless portals absolutely destroy our current understanding of all physics.

they do.

I agree with this. Unless there's a tube between the portals the answer is A. If there's a tube joining both reference frames, the answer is B. The latter following conventional physics, so B unless there;s no tube between the two portals, in which case, A's correct due to W = mad.

Shouldn't there be very strong tidal forces acting on the cube as it passes through the portal? The top part is trying to fly off, and the bottom part wants to stay still.

A because of 0 f, and there'd be zero distance i n the case of the portals being like a coin. There' however, would be distance if there's a tube between the portals, where the constant velocity of the portal's tube would be added to the acceleration of the orange portal's descension, making it propel.

So, are the portals connected via a tube, or not?

In reality they would have to be, thus B, becuase there'd be a constant velocity of v between the portals' openings.

Realistically, B. Only B. Like a wormhole

I'm drunk, so try to excuse my grammatical errors.

And from an inertial reference frame the cube will have both no velocity & some velocity when it is partially through the portal, which is impossible.

Unless there's a tube between them with a constant velocity of v. In which case, a is conserved.

Because the force of the object, would be ma, the mass accelerating through the portal at the rate of it's descension. Thus that a would be conserved through the constant velocity v of the portal. Does that make sense?

what do you mean by "tube"

I'm so drunk forgive me high IQ

I mean a tube enveloping all space between portals A and B. A tube enveloping ALL the space between portals A and B with an instantaneous velocity of v.

I don't understand, could you draw a diagram illustrating what you mean?

Or a constant gravitational pull of a, which wou;d add to the a of the portal's descension creating a1 + a2, meaning it'd fly out. Again, drunk but if there's gravitational acceleration of a in the portal's tube, the a's' d add up.

If there's a tube between A and B, there's a gravitational acceleration of a betweenm the portals. The acceleration of the portal's descension, a2, would add the acceleration from the tube's a1. creating an acceleration which would, effectively, propel the cube due to a2. Do you get it or not, because I am drunk lol

Basically a1 + a2 = overall a. There'd be an acceleration out of the portal due to overall a. If it's higher than the acceleration of g, it'd propel diagonally out of the portal.

If it's not higher than g, then it'd spurt to the bottom as per option A. How fast is the orange portal moving? Is what we need

What kind of "tube"? I still have absolutely no idea what you're talking about. Draw a picture.

It's going in at a rate of a1, a2 is the tube's acceleration, although can be substituted for vp, velocity of the portal. If a1 + vp > g, then the portal accelerates diagonally out of P assuming P has a g dragging the object at a constant velocity vp.The tube's acceleration = vp, a constant velocity with an accleration getting the object to VP. A is conserved in the tube of VP, meaning VP + A. From the reference frame of portal orange, of coursee

Forgot the picture, please forgive me and add to the previous post

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B. Because physics has no preference for frame of reference, and from the point of view of the piston moving downwards, it looks like its the platform shooting upwards.

_____ _____
V
=
______ __^__

The problem is ill-posed; the portals obviously shouldn't be able to move in relation to each other.

I was trying to demonstrate with ASCII art, but apparently Veeky Forums gets red of extra spaces, so I drew it instead.

except in B, the box has no kinetic energy, and then it goes through the portal all of a sudden it does. the portals dont do work. B is not possible.

It has kinetic energy relative to the orange portal though

only in the Z direction. when it comes out the other portal it has energy in the x,y, and z directions. something would have to to exert a force to change the momentum

No it doesn't because the object isn't moving. DOES the portal have mass? No, it doesn't; elsewise it would move the cube. No work is done, because the portal has a mass of 0. Work being defined as the amount of force necessary to move an object the distance of d, there is no mass, meaning no force, meaning no distance. The answer is A. No force is propelling the cube a diagonal Acceleration of A.

But the cube is moving relative to the orange portal

No force force is propelling the cube at a diagonal acceleration of A. There's no mass, meaning no force to propel the cube at any distance. The answer is A.

True but there's no mass = no work to MOVE the cube. The object pops up relative to it's location in the first frame. Which is STATIONARY. There's no V giving it momentum (mv) once the portal stops moving, giving it a mass of zero AND a velocity of zero. The momentum, p, of the cube is zero is ZERO due to the velocity of the propellant factor helping zero ONCE the ORANGE PORTAL stops moving. The P Is ZERO once the orange portal stops moving, meaning the object, whose velocity is contingent upon the portal's velocity, IS GOING NOWHERE. IT'S STUCK. IT SLIDES BECAUSE OF G AND THE ANTAGONIZING FORCE OF THE PLATFORM. THE OBJECT WILL, I REPEAT, WILL SLIDE DUE TO THOSE FACTORS. A

THERE'S NO FORCE, MEANING NO WORK, MEABING NO MOTION OF THE OBJECT. A

Work is DEFINED as the amount of force, F, to move an object a distance of d. Of the portal has NO MASS, F = ma, then there is NO FORCE, propelling the object. The answer is A!!

>Work is DEFINED as the amount of force, F, to move an object a distance of d
that's not actually how work is defined.
Work is the energy imparted on an object by some force F, through some distance D.
Answer is A, but you're making us look bad m8

Another easy way to see why its B is because the laws of classical physics should be time symmetric. If A was true then in reverse the portal would suck in the block as it was flying up passed the blue portal.

Alright, sorry. But unless there's a tube with a W of x involved, the answer is A.

>Newton's law of universal gravitation states that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

So EVEN IF the blue portal had a mass of X propelling the object CUBE towards it, the acceleration given by portal ORANGE, would become ZERO, after the end of the orange portal's desecension. Meaning no force propelling the CUBE... AWAY from portal blue, meaning NO DIAGONAL, OR OPPOSITIONAL FORCE

>If A was true then in reverse the portal would suck in the block as it was flying up passed the blue portal.
ayy lmao

But B would sick it in, meaning force necessary to propel it away from the force of B. THERE'S NO FORCE, NEGGAA. Or if there is a force it comes solely from portal B. The force of gravity added to the force of the blue portal would pull it towards the direction of gravity, which is down

Suck it in* damn you, autocorrect

Also I'm drunk

No B wouldn't. In reversed B the box has an initial momentum opposite to its final momentum. It flies into the portal in reversed B, no force is applied on it.

>NO DIAGONAL, OR OPPOSITIONAL FORCE

if m of portal B outweighs m of cube.

I said there was no force...neggaa

Lol

Although now I see what you mean. Still, if there's no m creating a t, then there's still no force. The portal B has to have a mass of m if the cube is at all attracted to it.

no momentum relative to the ground

No m creating a f, force.* autocorrect is my bane

So wait...did we effectively create an option C? Where the cube is stuck non-dimensionally inside of portal B?

So C...is..correct

In reverse B it loses its downwards momentum from the leaving the portal moving upwards at exactly the same speed it entered.

Easier way to see it's B is just to imagine the stand is small enough to go through the portal.

Except the acceleration of portal A adds to the acceleration of portal B. So if the acceleration a < g then A, if a > gtanB then B.

If a of b > gtanb

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Too drunk. but that should be enough for one to get the geometry (a + ag1)^2 > g2 then B.

>Too drunk. but that should be enough for one to get the trigonometry (a + ag1)^2 > g2^2 then B.

Logically, if a portal is just a hole, then the cube comes out of it just as quickly as it went into it.

People who say it's A because the cube isn't moving are looking at only half of the problem, but in the other half it is the portal that is stationary and therefore the cube that is obviously moving. B therefore perfectly conserves momentum. Furthermore, if you imagine that the orange portal keeps moving past the cube and that the cube is unaffected by wind resistance and gravity, you will see that the cube is moving away from the blue portal at the exact same speed that the orange portal is moving away from the spot where the stationary cube was, meaning that from the perspective of the orange portal, the cube still remains stationary if on the blue side it shoots off.

If anyone still objects that portals can't impart energy, I'd like you to imagine the opposite scenario, where you are standing still next to a stationary portal and step out through a moving one. Maybe just stick your head through. Is your head going to move with the portal, or is it going to be ripped off by mysterious forces as it tries to remain stationary in some objective frame of reference as the moving portal absconds with your likewise stationary body? Either way, you have to admit that some sort of mystery force connected to the portal is imparting some movement on your head.

Really, we've had countless of these threads on /v/ and while I've seen the advocates of B iterate and refine their arguments, the A side seems to be entirely stuck on the mistaken notion that the cube is "objectively" not moving, and an obsession with hula hoops. I think it's pretty thoroughly settled in favour of B.

>If anyone still objects that portals can't impart energy
you assume that portal machines are able to create infinite energy for free and with a strait face you claim that is a reasonable assumption.

don't you think if portals were to be a real thing that they shouldn't have that property?

>don't you think if portals were to be a real thing that they shouldn't have that property?
And how would they exist then? I'm not concerned with where the energy comes from. Just acknowledging that it has to be there.

if we aren't talking about a thing that could exist then shouldn't this conversation be on /v instead of /sci?

Because if we just accept the portals' existence then we're left with just a physics problem which doesn't require us to explain the portals to solve.

what force acts on the cube to cause it to have a velocity?

If you move the portal, you have to move the universe with it. And from both directions. So it's the force of the universe behind the cube.

I think in the game it would be A.
But in real life, where portals would most likely act with mechanisms, it would be B.

B is incorrect, The instantaneous acceleration would, however, cause it to tumble.

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why wouldn't B be correct?

There is no instantaneous acceleration, it will behave as if it was already moving at that speed.

If the bottom platform stays static, then A. Otherwise, B.

No, always B. The cube has to be moving to exit the stationary portal and it's not going to stop for no reason.

Isn't a portal just a hole? If you substitute the portal for a ring that simply falls around the cube, what would cause the cube to move?

According to the game Portal, the magnitude of the momentum is conserved when moving through portals.

Also the cube is moving when it is going through the blue portal so it should keep moving.

portals create a new frame-of-reference problem, nothing in the universe has an absolute velocity, any velocity is always relative to the earth's surface, or the center of the earth, or the sun. In this problem the cube has no energy in the frame of the orange portal but it does have energy in the frame of the blue portal

From my shitty understanding of this, since the orange portal being shot on top of the cube would be the same as the cube being shot through the orange portal, B would happen.

They can't have entrances that move except for that one Portal 2 level.

As the box's center of gravity passes the portal at t=0, the instantaneous shift in normal force will actually generate an infinity spin (theta squared divided by zero would be the angular acceleration value).

>If you move the portal, you have to move the universe with it
no, the pedestal the cube was resting on is still there, and now the cube suddenly has velocity relative to the pedestal? not happening.

B is correct

>you standing still, watch a train pass by
Do you have kinetic energy from the perspective of the train passengers? Obviously not.

Of course you do, what are you talking about?

wrong, kinetic energy doesn't work that way

It's mass times velocity squared, and obviously I have velocity relative to the passengers.

try to convert that energy to another form and see how that works out lol

Obviously you could convert it to another form of energy on the train. Are you thinking of the Earth's surface being an objective frame of reference here?

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checkmate