I'm confused

It will hit the back wall. Think about hanging a string and ball. Yes it's a bid different because the point of reference is the wait and not a string but the f=ma is the same.

>>8748283
it will stay in mid air because it is a closed system

If you smoke a sigaret on a bike it will make a funny youtube video. But will it do the same in a car driving 88 mph with all the windows closed?

There is your answer and a way to TEST and do the experiment YOURSELF

>>8748294
There are no forces acting on the heli before it hits the wall, so it will not accelerate in an inertial frame of reference.
Air resistance is negligible.

>>8748290
>It will hit the back wall.
This.

>>8748294
do you not move into the seat when you sit in a train?

When the train first starts moving, everything inside, including the air particles, would stay still, and thus "move backwards" (hence why people will lurch backwards during a sudden acceleration). As the air particles move backwards however, more and more will hit the back wall and bounce forward again, creating pressure away from the back wall due to the sudden influx of air, this might oscillate for a bit before eventually stabilizing, with the particles behaving pretty much the same way they were before except now with everything having added the speed of the train.

Since the helicopter only cares about the air it's suspended in, the question becomes how quickly this stabilizing happens. If it accelerated very quickly, the helicopter would probably hit the back wall, but it accelerated very slowly, I think it's also possible the helicopter might never hit the back wall, only moving back slightly, since the air has plenty of time to adjust. Couldn't give exact numbers though.

>>8748283
plane drifts to front of train car due to increased pressure in back of car

>>8748294
>>8748301
Please tell me you guys aren't this stupid. Please? Thanks heli will not accelerate with the train. It will smack into the wall.

>>8748283
It will move with the train.

>>8748500
Why?

Air pressure is the magic word of the thread

>>8748283
It is loosely bound to the train. It would crash and burn.

>>8748358
This.
Imagine the extreme situation - you're in an aircraft accelerating down the runway, do you notice any draft as the plane accelerates?
Pressure propagates through a gas at the speed of sound, so unless you're accelerating from zero to supersonic very quickly the gas will basically behave as an incompressible fluid and move with the vehicle.

>>8748283
Lol u tu4n le ghey

>>8748500
Maybe you should look up what inertial frames are.

>>8748534
Interestingly, if the helicopter was in a hermetically sealed train with the air evacuated, it would just sit on the floor because helicopters can't fly in a vacuum.

>>8748587
An accelerating train is not an inertial frame

>>8748608
u wot m8?

>>8748608
That's what the original quoted post claims.
It literally says that the object will not accelerate in an inertial frame, as there are no forces acting on it, and it will hit the wall.

>>8748294
>>8748290
>>8748337
>>8748500
Next time your daddy drives you around in a car, throw your special orange ball up and down. The orange ball didn't hit the seat, did it?

>>8748647
That's because the initial force applied to it by your hand is effected by the hand's movement in relation to the car, the helicopter would sustain flight if it had lifted off after the train had reached it's going speed, but if it lifted off before it wouldn't be effected by the train's movement and would stay still within its refference frame relative to the train and thus hit the wall.

>>8748283
The heli is in a medium of air within the train. As the train moves, the energy of motion gets transfered from train to air to heli. Therefore the heli develops inertia and moves with the train if the train gradually increases in speed.

If the train were to stop suddenly the heli would hit the wall as it does not have enough time to lose all that energy to the air.

it stays in mid air. the air is pushed with the train which pushes against the helicopter, forcing it to move together.

>>8748646
But it's not an inertial frame.
>>8748626
Frames that accelerate are non-inertial.
e.g. objects with no forces on them, don't necessarily travel in a straight line

>>8748682
>Frames that accelerate are non-inertial.

doesn't General Relativity's Equivalence Principle pretty much make them inertial?

Because the train has the force Forward and the heli does not. Because it is flying and therefore out of the FOR of the train (not including the air here). The air doesn't accelerate all at once either. The system is not closed when the train is accelerating.

There wont be enough transfer between the air and the helicopter to stop it from hitting the wall. Therefore the heli will not accelerate at the same rate as the train and will hit the wall.

Source: University mechanical physics courses.

>>8748541
>you're in an aircraft accelerating down the runway, do you notice any draft as the plane accelerates?

I notice increase g-forces though, seeming to be pushing me towards the back of the plane. (In actuality, the plane is pushing me forward trying to get me up to speed.) If I am dumb enough to be standing up, I'll get thrown towards the back of the plane.

Same will happen to a helicopter in a plane.

In a train, the forces are less. But they still exist. That is why, for example, they have those straps to hang onto on a subway train. When the train accelerates in any direction, contact with the floor, the seat, the strap, the air,all take a moment to accelerate me, or the helicopter, to the new velocity.

Whether forces might or might not "move" the helicopter enough to hit the wall depends on a lot of factors, but nevertheless, it moves.

>>8748647
Try it when he is accelerating.

>>8748294
No, there is nothing acting on the helicopter to make it accelerate with the train, it would apear to fly towards the back wall, now if it adjusted it's self to gain the pace of the train or took off when it was moving, it would be fine.

But the moment there is a change in acceleration, the helicopter will move.

>>8748698
Quite.
Hence why I said "this" in relation to a previous comment.
The helicopter has inertia, same as everything else, but it won't stay exactly in place as the train moves forwared and collide with the wall of the train - it gets dragged along with the air in the train.

>>8748717
What if the helicopter is quite heavy?
The force acted upon it by the air might not be enough to accelerate it enough to counteract the acceleration of the train, no?

>>8748290
This
>t. RC enthusiast who tried the same experiment in a car with a quadcopter

>>8748710
There is the air. The air accelerates pretty much with the train, which would tend to accelerate the copter. So depending on things like the density of the helicopter, how much surface area it presents towards the aft of the train (and thus how much the accelerating air pushes on it) etc, and of course on the acceleration of the train, it will appear to move back to a greater or lesser extent.

I am surprised nobody has put a treadmill and an RC plane on our hypothetical train yet.

Just draw a free body diagram

>>8748283
oh boy another slightly ambiguous bait post again...

>>8748771
where do you see bait in there?

The helicopter will be moving at the same speed as the train. When the train comes to a stop, it will continue to move forward and crash through the glass.

I couldve answered this question before i learned the alphabet. Op apparently learned the alphabet first.

It's going to hit the wall, the air provides the only horizontal force to move it and I suspect it wont be enough(supposing the train accelerates fast enough).

>>8748587
>>8748294

It's no different than a helicopter hovering above a flatbed truck, idiot. The roof makes no difference.

>>8749071
>The roof makes no difference
On the contrary, the helicopter would behave very differently if it were on a moving train with no roof.

>>8749071
On a flatbed truck, the uncontained air would not forward when the truck did. On a train, the enclosed air does move forward when the train does.

>>8748283
>there is currently a debate on the answer of this easy as fuck bait post

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>>8748604
truly enlightening

>>8748283
When the system is at rest we have [eqn] \sum _{i} F_i = m \ddot { \vec { a } } = 0 [/eqn]Now consider a moving system, then we have a position vector that looks a bit like [math] \vec { r }_0 = \vec { R } + \vec { r }' [/math] where [math] r_0 [/math] is the position from the origin of a stationary frame to a point, [math] r' [/math] the position of the particle to the origin of the moving frame and [math] R [/math] is the position from the origin of the stationary frame to the origin translated frame. Differentiating: [eqn] \vec { v } _0 = \dot { \vec { R } } + \vec { v }' \\ \implies \vec { a }_0 = \ddot { \vec { R } } + \vec { a }'[/eqn] So clearly we have an additional acceleration, which is from the accelerating frame, and so the helicopter will move.

>>8748647
kek

To those who think that a train accelerating has no effect on it's contents, explain what happens when a train decelerates rapidly, and why it's different.

>>8749822

>dots on top of \vecs


that has to be the most retarded thing I have ever seen in my life.

>>8749838
>\vecs on top of dots

Horribly unaesthetic.

>>8749839

how about you use \textbf and not \vec?

that's what the pros do.

>>8749842
But then what will I use for matrices?

>>8749849

caps or hats. Plus most of the matrices in classical mechanics are tensors, anyway, and you could use that gay-ass double arrow if you like.

>>8749859
>caps
Plebeian

>hats
Operators

>Gay ass double arrow
We've come full circle

>>8748647
Go funny but so wrong at the same time, damn.

>>8749865

physicists typically don't care to distinguish between operators and matrices.... but caps still work, that's my recommendation, because the \vec is bad notation.

I had an exam earlier where I genuinely wrote [math]\ddot {\vec {\tilde x}}[/math]

Fucking fight me

>>8749900
There is nothing wrong with this notation.

>Fucking come at me.

>>8749822
>second derivative of acceleration

https://youtu.be/y8mzDvpKzfY?t=4m10s

The helicopter is "suspended" in air, not lighter than it. So it moves with the airmass, not against it. The train accelerates slowly, so it would eventually move forward, but would go backwards first.

>>8748290
Newton's Laws of Motion do not apply here because this is not an inertial frame of reference. Unless, of course, you redefine Force.
The helicopter will hit the wall, just as would a passenger without a seatbelt when a car accelerates to a stop hit the windshield.

>>8748692
yeah, that's why relativity is so important. Relativity finds ways to redefine Force and gives us the acceleration at any point in the warped fabric that is space-time in our system. Newton's Laws, however, only hold in an inertial frame of reference, i.e., one that is not accelerating.

>>8748283
It wont actually move forward or backward, it will just tilt forward as all the air piles into the back bottom corner of the train.

>>8748283
It depends on whether the train is hermetically sealed. If it is, then it's a closed system, and the helicopter will stay mid air. If there's at least one small hole/window/opening/whatever in a train, the helicopter will smack against the wall like a fucking Mexican.

ITT: a bunch of brainlet faggots.

This is intro physics. It will hit the back wall.

How stupid can people be? The rotors only cancel out the gravitational force, which is vertical, thats why it hovers. When the train stars moving, nothing makes the helicopter move with it, except for the air in the train causing a "wind" (as seen from the trainstation point of view). This "wind" is the only thing causing a horizontal force on the helicopter, which will accellerate it, but far slower than the rest of the train is accellerating.

tl;dr
Helicopter will accellerate along with the train, but not at the same speed as the train.

>>8750285
it's not touching any part of the train dumbfuck. The helicopter is in equilibrium and is not moving at constant velocity. It's just sitting there. When the train accelerates, there's no reason to assume that the helicopter starts to accelerate with no outside force acting on it. While the train moves from point A to point C, the helicopter perpetually hovers at point B until the point when the train smacks that bitch like Ray Rice

>If you crash a car do you get knocked forward?
Yeah of course not

https://www.youtube.com/watch?v=sI8ldDyr3G0

The ISS is full of air and the things inside it don't get magically pushed along by that air instantly when it accelerates. The helicopter in OP would move towards the rear wall.

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>>8748283
I've done this with a tiny quadcopter. You have to adjust for drift in odd manners, since the train is almost always accelerating/decelerating, but it is very easily possible. It is easy to take off AFTER the train is moving. If it takes off before the train moves it will drift faster but that is negated almost instantly with adjustment.

>>8748299
You can see it better when you have a thick smoke stream then make a sudden turn.

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>>8748283
You dumb fucks...
M.S. Aerospace Engineering
I will answer this in a way even the DUMBEST of you fucks will understand.

FART... does the smell magically disappear when the train starts.... NO... the air moves with you... the AIR WILL move and compress on acceleration but then restabalize... the helicopter will move a bit at first then stabalize. It MIGHT hit the back if you took off like at bullet speeds , but otherwise it will move a few feet then hover still again.

>>8750544
/thread

>>8750544
the question is specifically about accellerating, not just a moving train.

>>8750295
read more carefully, he said that the heli will be very slightly accelerated due to the air in the train pushing against it. it's almost nothing but it will hit the wall a tiny bit later than it would in a vacuum filled train

>>8750594
>if I blow on an object it will move with the same speed as the air coming out of my mouth

>>8750621
Which was totally answered in >>8750544

lol you got cucked, friend.

nice b8 m8

>>8748283
I goes towards the door because of pressure escaping.

>>8748299
>sigaret

The helicopter will stay in place and continuously accelerate in motion to match the motion of the train. After the train has reached peak speed, the helicopter will gradually continue its forward acceleration, and after a short time period it will be moving fast enough to break through the doors separating the train carts, and will ultimately bust through the locomotive's windows. The helicopter will proceed to continue on this path of linear velocity, while also ignoring its terminal velocity. Reports come across the world of RC helicopter shaped holes in buildings and city structures, and NORAD reports that they've tracked a hyper-sonic UFO with the radar signature of an AirHogz RC helicopter exit the earth's atmosphere.

>>8748283
Train is Earth. Earth is moving faster than any other train combined and multiplied by themselves. Throw a ball upward. Does it fall on the ground, or does it fly away?

there you go..

>>8749900
there are not words to express my anger
only
[eqn] R \prod_{-\infty}^{\infty}E [/eqn]

The air inside the train car is also accelerating. If the train sped up at a slow enough rate, the drone would stay in place.

Why you lurk on a science board if you are a brainlet??

Jesus just search a video for fuck's sake:
https://www.youtube.com/watch?v=gnXf7EJ8Qvc

>>8748647
If he accelerates after you release it, yes.

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>>8750544
brainlets BTFO

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>>8754074
>posts a shooped image
>calls us brainlets

At least you tried.

>>8748717
It will not get dragged along with the air. Everyone ITT is way overestimating the effects of air.

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>>8754076
>shooped image

the train is a partially sealed space. the flux of the enclosure through the medium of air will produce air currents that will affect the helicopter.

the effect is because of he different velocities of the air in the station, and the respective air partial container.

if it were a total container, the air cushion is an independent reference frame at a constant velocity and the copter is unaffected.

>if im going at the speed of the milky way, why does everything around me look so slow?

>>8753534
You hover a helicopter over the ground. Relative velocity is 0. Then a kilometer high wall comes flying towards you at constant speed. By your logic, the wall will not hit you, which is retarded.

>>8750544
>>8753990
THIS IS FAKE DELETE IT

It's gonna depend on how fast the train accelerates.

>nofunz detected
The fact that you even need to ask means that you have never thrown something up in an accelerating car just for the shits.

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I bought a quadcopter once and flew it in my friend's car while he was driving. If it was already airborne before the car moved, it would move all the way to the back of the car and crash.
If the car was already moving before it took off, then it would move with the car for a bit and then fall back.

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Brainlets don't get this thought experiment, so I will help you.
Imagine the air inside as water, like an aquarium. Now start moving the system, what will happen to the submerged objects? They will get disturbed by waves and shit, hitting the fucking wall.