/sci/ btfo

the bear will wake up instantly because the speed of wood is greater than the speed of light, it's basic physics

>>8815010
you have neglected how long it takes the finger to touch the wood, which is the speed of thought. therefore this violates casuality.

>>8815014
fuck

>>8815000
why wouldn't this work?

are physicists really this retardeed?

>>8815000
however long it takes for the speed of sound in the stick to travel 1 light year

>>8815000
its instant

2.867 trillion seconds

1 light year divided by 3300 m/s (speed of sound in wood)

>>8815055
>>8815064
why the speed of sound? I'm assuming OP's pic is intended to show the stick moving. Isn't this supposed to imply the whole stick moving instead of sending a shockwave through the stick?

In that case the maximum speed with which the molecules in the stick could affect each other is the speed of light, so it'd take one year for the bear to wake up. Right?

>>8815047
Nothing is perfectly rigid. It would take time for the motion to transit the length of the stick.

>>8815071
>affect each other is the speed of light

No, c is just the maximum possible speed force can be transmitted, not the average actual speed.

How are people comfortable with air only being able to carry the force of your vocal cords at around 330 m/s but totally lose their shit at wood also transmitting force at less than the speed of light.

>>8815088
Not one year though.

>>8815109
so denser objects transfers force faster?
if the stick was made of most dense matter possible, how fast would it be?

It takes 1 light year obviously, can't you read?

>>8815109
OK, how about the scenario where you're rotating a stick of wood around. Would it still only be the speed of sound in wood? My intuition says that it wouldn't.

The speed of sound is also affected by pockets of air etc in the wood, but the way the molecules within the wood interact with each other isn't, right?

>>8815000

1 year.

>>8815109
>No, c is just the maximum possible speed force can be transmitted, not the average actual speed.

This is the most retarded thing I've read on /sci/ today.

>>8815000
Asauming a stick 2 cm in diameter, that stick would have a mass of about 2*10^15 kg, or 30 times the total biomass on earth

The bear would wake up whenever it feels like it, because you'd never be able to push it enough to wake it up

>>8815118
>so denser objects transfers force faster?

Yes, because molecules/atoms/ions are closer together, thereby reducing the translational energy distance.

If you knock a wire of 100 balls and a wire of 10 balls over a 1m wide room, using the same and sufficient force, the 100th ball will absorb the system's energy faster than the latter.

>>8815141
incorrect, the bear would wake up instantly because it would get startled by the air being sucked out of its lungs due to the vacuum in space

>>8815131

If you rotate the stick, the end would take 1 year to activate.

The stick would be curved for 1 year.

>>8815149
Right. So why is it the speed of light all of a sudden and not the speed of sound in wood?

>>8815110
It would take much, much longer than a year. As mentioned already, the molecules in a "rigid" object move at the speed of sound for that solid, not at the speed of light.

>>8815140

What's wrong with the statement?

>>8815000
depends on how long the bear usually sleeps

>>8815153

Because the wood is a visible object. Sound is not a visible object.

>>8815218
Come on guy, don't be an asshole

>>8815000
Instantly due to the immense gravitational pull of the wood

>>8815000
if the stick is one centimeter in diameter, the volume is roughly 7.43 x 10^11 cubic meters.

Light wood has a density of about 400 kg/m^3, so this stick would weigh at least 2.972 x 10^14 kg. This particular level of mass is larger than most man-made structures (Empire state building is something like 9.8 x 10^8 kg) but smaller than most large-ish celestial objects (the moon is about 7.35 x 10^22 kg).

So consider how long it takes to push a stick weighing about as much as a small asteroid a few inches (on a surface with Earth-like gravity, based on the way the bear is sleeping) accurately into a bear one light-year away using only one finger. Then you can say /sci/ btfo.

>>8815000
AFAIK it takes bears seconds to minutes to wake up.

>>8815153
>why is it the speed of light all of a sudden
It's not. >>8815149 is incorrect.

>>8815266
Thanks

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>>8815000
How long? Well, the real question is how long does it take for a sleeping bear to wake up on its own?

A perfectly-whittled stick of oak wood about an inch in diameter would weigh 10,824,750,000,000,000 lbs. 10 quadrillion pounds. That's greater than the mass of 8 earths if I did the math correctly. I'm not the best at math.

Anyways, you'd never be able to push the stick at the bear. because it's too massive. Thus, the bear will wake up whenever it feels like it.

>>8815000
the bear would never wake up as the force projected into the stick would be fully absorbed by the system (the stick). This is a piece of fucking wood we're talking about here, not carbememe; even if you falcon punched one end of the stick the other end wouldn't even twitch.

>>8815309
The bear WOULD wake up, as a bear naturally waking up is independent of whether or not you poke it with a stick.

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>>8815071
>Isn't this supposed to imply the whole stick moving instead of sending a shockwave through the stick?
you moving an object is you sending a shockwave into the object and that shockwave being reflected back onto you as you continue to push it forward
this happens on scales so small that the speed of sound in a solid object appears to be instantaneous to you
on larger scales this difference is significant

think about how a train locomotive pulling/pushing multiple cars pulls/pushes them all in lockstep. Now imagine there's a whole lot of cars (atoms) in the train (stick). The amount of time it takes before one car is affected by the motion of the locomotive is proportional to the speed at which the locomotive moves (speed of sound in the stick) and the distance from the locomotive to that particular car (distance between the hand moving the stick and the atom some ways down the stick).

>>8815110
t. brainlet

>>8815064
>speed of sound in wood is Mach 10

At first I was shocked but now that I think about it this totally makes sense. Is wood 10 times denser than air?

>>8815366
thanks bud, I appreciate the explanation

>>8815010
>the speed of wood is greater than the speed of light
why did I laugh

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>>8815014
I have absolute no clue what this means.
Why did I decide to go to board surf to /sci/?

>>8815405
same here, I saw this thread on the front page and came here, don't know what to expect

I'm having a good laff tho

>>8815014
wrong, there is only one speed that is instantaneous and it is the speed of love

>>8815000
>>8815010
>>8815047
>>8815055
>>8815064
Speed of sound in wood is 3x10^3 m/s. Speed of light is 3x10^8 m/s. So about 100,000 years.
>>8815390
>Is wood 10 times denser than air?
Try 500 times denser. Density actually reduces the speed of sound, but wood has a much higher bulk modulus (i.e. it is stiffer) than air.

>>8815436
>(i.e. it is stiffer)
Interesting. Does that mean that the speed of sound is higher in an erect penis compared to a flaccid penis?

>>8815071
Just intuitively, you've seen slow motion videos, right? Like a boxer getting punched? The mechanical waves from the deformation (punch) take time to travel across the guy's face. It would take the same amount of time for any type of mechanical defomration to arrive as sound (since it is a mechanical deformation)

>>8815390
Mach numbers are defined not relative to air, but the material the wave/object propagates in. Mach 1, but much higher than air speed.

>>8815000
1 light year/speed of sound through wood.
Nigger

Bymp

>>8815149
How many revolutions would it take for the far end to turn at all? The stick is elastic, if you turn it it will be in a state of tension until the effect travels to the other end. If you turn it too fast, the mass of the stick is too great and it can not take the torsion, and will just break. If you turn it a few thousand times it would still be barely noticeable but the stick should be quite a bit shorter.

>>8815000
I'm studying geology, since you're creating an earthquake wave in the stick I would say about 1~14 km per second.

http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/waves_and_interior.html

So let's say between 21,000 and 300,000 years

>>8815000
It says in the picture

1 light year

>>8815000
Depends how sleepy the bear is

1 light year. Kinetic energy will propegate as a wave through the stick.

>>8815000
Light years don't measure time, dumbass. They measure weight.

And you've given the fucking answer in the picture, you would only need to weight 1 light year.

The gravity of A light year long stick causes the beard to be impaled on the stick.

>>8815145
You have literally just confirmed Alcubierre.
With a fucking stick.
On a photonic enriching gastronomy board.

I don't know whether to congratulate you or hit you with it.

>>8815000
But the important question is, how much would that stick weigh?

>>8815118
With an impossibly dense material he would wake up with the speed of light.
Implying you could even move something with infinite mass.

To all the fags assuming a shockwave in the wood, why wouldn't such a wave dissipate into heat before it reaches the bear?

>>8817354
This. The only feasible way to touch the bear through the stick would be to move it whole, and that's assuming it doesn't implode due to the sole fact it's a light-year long stick.

>>8815366
but before one atom can touch the next atom it has to travel half the distance to it, and before it can travel half it has to travel a quarter and so on

/sci/ btfo yet again

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>>8815000
the speed at which you push the stick, which can never exceed the speed of light.

10/10 for getting so many replies though!

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>>8815000
the speed of stick of course