What would happen if the counter weight was traveling at or just below light speed while falling down, what would happen to that projectile stone? Or to the longer part of the lever? Of course they can't travel faster then light speed. So what would happen to the stone and to the longer part of the lever?

I love SpaceTime. It's kind of a sad statement about humanity that we're simultaneously talking about understanding the universe and killing each other with big rocks. I still love SpaceTime.

Lol Great video ðŸ™‚ I made 3 trebuchet's for hacking the clock and the future ðŸ™‚ (and history (R)0fl what a blast , the internet , lol sending data over the the clock and the firewall ðŸ™‚ air resistance lol Clocks in Win CE hehe ðŸ™‚ Drivers are fun make ðŸ™‚ clock Bios "shots " lol

I have a question regarding black holes (I know it is very off topic but I lack the knowledge to figure this out). Say a space ship approached a black hole but did not cross the event horizon and kept a sizable distance. Now assume it "lowered" a cable with a tiny weight on the end (like a fishing line) until it just passed the event horizon. Assuming the cable had infinite strength and no weight besides the actual weight on the end, would the ship be able to reel in the cable or would the ship be spaghettified? Also, depending on the size of the weight and if it could be reeled in, what kind of forces would be required?

Hi please can u do a video about the theory of the electrical universe. Why it is not accepted as a realistic theory, I am intrigued by some of the points of it, if not quite all. Thanks

Can u guys plz make a video on photo current and frequency relation ….m finding way different answers on internet….can u guys make a series on potoelectric effect…

Point 1), that would have to be the most condescending Scholar's Cradle ever posted to YouTube…(!).

Point 2), if the Bucket starts from the same height with both throws, launching Projectiles of equal Mass/Surface Area…, then it doesn't matter if the Projectile is launched early, climbs high, and then falls steeply – or if launched later and flies a flatter trajectory…; either way it begins with the same amount of Energy in the Bucket, so the Impact-Energy will be identical, regardless of the Launch-Angle, storing Kinetic Energy by converting it to Gravitational Potential via Altitude – & then reversing the Conversion by falling down….., doesn't increase or decrease the Impact Energy.

So i have a sort of related question. If rockets are taking off and never really returning to earth, do we have to worry about changing the earths orbit?

ReplyJessica Van RensburgMarch 2, 2018 at 10:53 am

How fast is the stone travelling AT the moment of impact … does he really mean just before impact or this a trick question ðŸ™ˆ

I have a question regarding the extra credit question: does the projectile travel 300 meters upward (vertically) or do you mean that it travels 300 m towards the fortress (horizontally)?

Probably not the best comment to make but, would you poke the proverbial dragon and do a video showing why planets are spherical in a way that someone who doesn't believe can not argue with almost reason? Sauce did a good job I know you can to. There's a spread of flat earth people that's getting too big.

Answer for the first question. Shot with horizontal trajectory will cause more impact. Shot with vertical trajectory will cause less impact because at a point in the air its velocity becomes zero and it starts to fall with aacceleration of 10 meters per second. It is no longer in influence with initial velocity given by the trebuchet.

What if the universe is a giant quantum AI where all the possible outcomes have and will happen, and we're all just a complex representations of 0's and 1's. Where evolution is just a complex form of compiled data. As a bonus to back up this hypothesis, the universe is cold and electronics perform best in cold conditions.

I'm going to be a stick in the mud and interrogate this entire preoccupation with classical physics. What is the point in doing exercises in classical physics, if classical physics is an emergent phenomenon of quantum mechanics?

Regarding the Treb as the greatest medieval siege engine: J.E. Gordon argues in 'Structures', that the treb had limited energy storage and low efficiency compared to the (then-forgotten) Roman ballista. Gordon claims the ballista was 10x more energy efficient, due to energy stored in its arms being re-transferred to the projectile, while most of the treb's energy was wasted in the arm/braking mechanism.

Question: say we discover a dark energy particle. Can we blow up a black hole by shooting dark energy particles into it, which ought to expand the space inside the Event Horizon?

Chemists use conservation of energy in the form of Hess's law: the net change in energy from a reaction is always the same, whether the reaction is run forwards, backwards or with any combination of intermediate steps, as long as the start and end points are the same (same amount of starting reagents and end products). In biology this is important because the theoretical energy output from burning a lump of sugar is the same as digesting and metabolizing that same amount of sugar. In other words, the law of conservation of energy says that humans are effectively the same as a forest fire.

question one, I believe from what I understand form the constant acceleration equations is that they will impact the wall with exactly the same force, neglecting air resistance and; moment of velocity in which they are released because the impacted at the exact same point therefor they most have the same v0, but this only applies if the height is equal at both points which I would infer that its. second question is pretty lengthy depending on the system of equations or the one equation that you learn at the end of physics 109 that teaches you everything you just learned in one equation, but because I'm tired at the moment ant wish to sleep the answer is M1 x 9.81 m/s^2 x the seconds that it is falling from the peak of the parabolic arc, neglecting air resistance.

Could you please do a video on ToE. I dont get why people talk so much about string theory and not LQG. I came across this opinion which pretty much sums up most of my thoughts on , with the expection that I like the idea of a ER=EPR and the holographic principle. The current picture of the Universe physics offers is that of interacting quantum fields. The theory of those quantum fields (i.e. the right QFT) is constructed by quantizing the corresponding CLASSICAL theory. Gravity is a field whose classical theory is general relativity (GR). So what should be done is to quantize general relativity. This is a challenging task, since general relativity (unlike other field theories) doesn't live IN a background; rather, the metric whose dynamics GR describes IS the background. This feature of general relativity is called background-independence. By switching to Ashtekar variables, the standard procedure of canonical quantization can be (and has been) applied to the GR Hamiltonian. The resulting quantum theory is known as "loop quantum gravity" (LQG). The theory (1) gives a model of the quantum geometry of spacetime, in which area and volume operators are quantized; (2) features background independence; (3) has been shown to reproduce the Bekenstein-Hawking entropy formula for all black holes (not just extremal ones as in string theory); (4) has been shown to have the correct semiclassical limit in various special cases (through the so-called Master Constraint Programme); (5) has been applied (albeit in the form of a toy-model) to cosmology, replacing the Big Bang singularity by a quantum "bounce". Current reserach directions include: (6) a purely combinatorial treatment of the dynamics (Algebraic Quantum Gravity) (standard LQG quantizes the metric but retains the continuum because the manifold is still used in the formulation of the dynamics; AQG is an effort to do away with the background manifold, hence the "purely combinatorial treatment"); (7) Checking that the theory reproduces GR in the classical limit; (8) the search for phenomenological consequences; (9) construction of a covariant formulation of the theory ("spinfoams"); (10) the possibility that unitarity is not lost in the process of black hole formation+evaporation; (11) the coupling of the theory to quantum matter.

Now that's the most promiment (although not the only) example of sensible quantum gravity.

Now, what about string theory? String theory starts as a (failed) theory of the strong nuclear force. When Quantum ChromoDynamics (QCD) was shown to be the correct theory of the strong nuclear force, string theorists realized that the formalism of string theory could be reinterpreted as the formalism of a unified theory of quantum forces including gravity. They were excited when they discovered that "graviton-graviton" string scattering was well behaved. Nonetheless, the framework had (and still has) a lot of problems, mainly:

1) it needs supersymmetry (SUSY) in order to be physically consistent. SUSY still doesn't show up, and has lost much of its initial appeal. 2) it needs a 9+1 -dimensional spacetime in order to be mathematically consistent. Since we live in a 3+1d world, the (entirely ad hoc) assumption had to be (and was) made that the extra 6 spatial dimensions are "compactified" at the Planck scale. Problem is, there are 10^720 different ways to compactify those extra spatial dimensions (in structures called "Calabi-Yau manifolds", corresponding to different "string vacua") and the physical predicions of the theory strongly depend on which one you choose. The solution to this problem? Hello multiverse! 3) it is a perturbative, background dependent framework, which means it assumes a flat background spacetime on which gravitons propagate. This amounts to a failure of taking seriously the main conceptual lesson of GR. 4) the formalism is based on Feynmann diagrams, which (at least to date) are not mathematically rigorous. 5) the theory is non-unique: there are five versions of perturbative superstring theory.

There is an additional problem of a sociological character, which is that string theory is mostly done by particle physicists, who rely more on heuristic arguments and "physical intuition" (whatever that may be) than on rigorous mathematical manipulations (often without even knowing this is the case, as happens for example with path-integrals), and who tend to be philosophically lacking and conceptually narrow-minded.

What Witten did is to give plausible arguments for what is still a conjecture: the existence of a nonperturbative, background independent, 10+1 -dimensional quantum theory involving not only strings but other extended objects of superior dimension (called "d-branes"), which would give the five different string theories and 11D supergravity (a unified theory candidate which was popular at that time, which basically was the result of GR + SUSY) as different limits. He called this to-be theory "M-theory". Another important (and also still unproven) conjecture was the AdS/CFT Conjecture by Maldacena, which posits a duality between n-dimensional M-theory in an Anti-deSitter (AdS) spacetime and a (n-1)-dimensional conformal field theory (CFT) living in the boundary of such spacetime. What string theorists did was to act as if that was a proven conjecture, and then to make even bolder conjectures of increasing level of delirium, such as the "holographic principle", "spacetime from entanglement", "ER = EPR", "it from qubit" and the latest piece of schizophrenia by Susskind, "QM = GR".

So, at a theoretical level, M-theory doesnÂ´t even exist as anything else than a pile of unproven conjectures. Accordingly, superstring theory is not the leading candidate to a ToE (the leading candidate for Quantum Gravity would be LQG and the leading candidate for unification of the forces is probably ConnesÂ´s programme of noncommutative geometry in physics, particularly the Spectral Standard Model and the more general Spectral Pati-Salam Model).

And at a sociological level, the superstring approach is indeed the most popular one (although its popularity keeps declining) because we have too many high-energy physicists and so few mathematical physicists.

E = mc^2 KE = 1/2 mv^2 Watching this video, this occurrence came to mind: I see interesting similarities considering that c IS a velocity. It's interesting to me that when v=c, E=KE can only be satisfied if m=0, and, coincidentally, a photon IS mass-less. (and, yes, I do understand that technically E=mc^2 is only completely true for an object at rest and so completely does NOT apply to kinetic energy, but the similarities in the equations IS interesting, nonetheless)

2nd shot does most damage. Mainly because of Gravity increasing its speed down. And because of the Force of Impact is mass X velocity wich is increased if you add gravity with it. 9.8M/S if the projectile is high enough it will reach terminal velocity and crush basicly anything thats below it.

(I didnt use any maths or what so ever. Just basic knowledge of gravitional pull. Feel free to correct me)

But if I'm playing as a Briton I get bonus splash damage with Warwolf… how do I factor that into my equations? Also, siege Engineers gives a bonus 20% damage to buildings once researched, so should I provide answers with this additional 20% included or assume the player hasn't got enough spare wood?

Hmmm I wrote down the solution like 2 weeks ago (would've been still one week to send it in) and since then it lies around on my desk. What's wrong with me that I'm this lazy? xD

1st Q: The damage is the same in both cases. The amount of energy in the projectile does not change (no matter the trajectory) since only conservative forces are acting on the projectile.

2nd Q: If you want to skip the detailed proccess: V = 66[m/s] or V = 75[m/s] depending on assumptions.

2.1 – Find the âˆ†PE to determine how much energy was transferred from the counterweight to the projectile. âˆ†PE = PE_1 – PE_2 = (m_c)*(g)*(h_1) – (m_c)*(g)*(h_1) Where: âˆ†PE = change in potential energy PE_1 = counterweight Potential Energy at position 1 PE_2 = counterweight Potential Energy at position 2 m_c = counterweight mass h_1 = counterweight height at position 1 h_2 = counterweight height at position 2 m_c = 5[ton] = 4535.92kg âˆ†PE = 4535.92[kg]*9.8[m/s^2]*8[m] – 4535.92[kg]*9.8[m/s^2]*2[m] âˆ†PE = 355616 [kg*m^2/s^2] – 88904 [kg*m^2/s^2] âˆ†PE = 266712 [kg*m^2/s^2]

2.2 Then we can find the release velocity of the projectile with the Kinetic Energy equation (solving for velocity) and assuming that all the Potential Energy lost by the counterweight went to the projectile.

KE = (1/2)*(m_p)*(V_r^2) = âˆ†PE Where: KE = Kinetic Energy m_p = projectile mass V_r = projectile release velocity KE = (1/2)*m_p*V_r^2 = âˆ†PE Solving for V_r V_r = sqrt((2*âˆ†PE)/m_p) V_r = sqrt((2*266712 [kg*m^2/s^2])/90[kg]) V_r = 76.99 [m/s]

***If the projectile would have been launched at the same height it crashed (either 0 or 15 meters), the problem would have ended here since the initial and final velocities would be the same in the "x" and "y" axis. But since there is a change in height, it means that there is a difference between the initial and final velocity in the "y" axis, although in the "x" axis it remains constant therefore the velocity vector has to be decomposed.

2.3 Separating the release velocity vector into its "x" and "y" axis components: V_r = sqrt((V_r_x)^2+(V_r_y)^2) V_r_x = V_r*cos(Î±) V_r_y = V_r*sin(Î±) Where: V = Velocity vector V_r_x = release velocity vector component in "x" axis V_r_y = release velocity vector component in "y" axis Î± = projectile release angle V_r = sqrt((V_r*cos(Î±))^2+(V_r*sin(Î±))^2)

2.4 Finding the impact velocities in the "x" and "y" axis: Assuming projectile release angle (Î±) of 45 [deg]; (since it wasn't provided in problem statement) Assuming V_r_x = V_i_x (release and impact velocity in "x" axis is constant) From section 2.3: V_r_x = V_r*cos(Î±) Therefore: V_i_x = V_r*cos(Î±) = V_r_x V_i_x = 76.99[m/s]*cos(45) V_i_x = 54.44[m/s] Using the following equation for the change in velocity in the "y" axis: âˆ†V_y = -sqrt(2*(g)*(âˆ†h)) âˆ†V_y = V_r_y – V_i_y where: âˆ†V_r_y = change in velocity in "y" axis âˆ†h = change in height in "y" axis = 15[m] – 0[m] = 15[m] V_r_y – V_i_y = -sqrt(2*(g)*(âˆ†h)) Solving for V_i_y: V_i_y = V_r_y – sqrt(2*(g)*(âˆ†h)) From section 2.3: V_r_y = V_r*sin(Î±) Therefore: V_i_y = V_r*sin(Î±) – sqrt(2*(g)*(âˆ†h)) V_i_y = 76.99 [m/s]*sin(45) – sqrt(2*(9.8[m/s^2])*(15[m])) V_i_y = 54.44[m/s] – 17.15[m/s] V_i_y = 37.29[m/s]

2.5 Finally, for the impact velocity (V_i): V_i = sqrt((V_i_x)^2+(V_i_y)^2) V_i = sqrt((54.44[m/s])^2+(37.29[m/s])^2) V_i = 65.99[m/s] â‰ˆ 66[m/s]

my question to you is whether your 'FIRST Question situation' is actually possible in a Trebuchet?? Can there be 2 release points that give away same amount of energy to the Stone when the initial release height is the constant?

Energy transfered into projectile = Potential Energy lose from counterweight. Counterweight is 1m off the ground, the counterweight's maximum potential energy is at a height of 7m and finishes at 1m.

PE(start)=KE+PE(Finish)

mgh(start) = mgh(finish) + 1/2mv^2

(5000×9.8×7) = (5000×9.8×1) + (1/2x90xv^2)

343,000J = 49000J + 0.5 x 90 x v^2

KE = 294000J = 0.5 x 90 x v^2 v^2 = 6533.3333 v = 80.829m/s

basic highschool physics this.

Before anyone flames me, this is done weeks after the challenge. Cos I never watch videos on time anyways…

Even simpler, you could just do 5000×9.8×6 = 1/2x90xv^2. You don't even need to know the lowest point of the trebuchet counterweight. All you need to know is how high it rebounded to know how much energy it lost to the projectile. The trebuchet arch could be 20m and come back up to 14m and the answer would still be the same.

The trebuchet animation doesn't accurately show the motion of the counterweight. The reason counterweights are mounted on a rigid arm like that is that it lets them fall in a straight line for longer so when the throwing arm is vertical the counterweight should still be in front of it, tilted at an angle.

Finally!!! Maybe now people will stop using the term energy wrong!

ReplyDyslexic Artist Theory on the Physics of 'Time'June 17, 2018 at 5:25 pm

This is an invitation to see a theory on the nature of time! In this theory we have an emergent uncertain future continuously coming into existence relative to the spontaneous absorption and emission of photon energy. The future is unfolding with each photon electron coupling or dipole moment relative to the atoms of the periodic table and the wavelength of the electromagnetic spectrum. This is part of a universal process of energy exchange that forms the ever changing world of our everyday life.

I feel like it would partially depend on what the exact target is. But if its only speed its neither of them or both of them. Both arcs are going to lose and gain speed at different degrees but find equilibrium. Also its travelling 0 speed at the moment of impact its released that energy into what I assume would be kinetic energy into the target.

Man when I was in High School, I built a bad ass trebuchet. The trick is having a fulcrum on wheels. I had a track for the wheels that was the fulcrum. The counter weight would fall straight down maximizing potential gravitational force.

## 100 Comments

What would happen if the counter weight was traveling at or just below light speed while falling down, what would happen to that projectile stone? Or to the longer part of the lever? Of course they can't travel faster then light speed. So what would happen to the stone and to the longer part of the lever?

And some one explain the answer to me please? I am stuck at finding the K. E of the projectile. Thanks

Well my head just exploded thinking about the math. No tshirt for me. Still love the videos.

I love SpaceTime. It's kind of a sad statement about humanity that we're simultaneously talking about understanding the universe and killing each other with big rocks. I still love SpaceTime.

Too easy man, too easy.

Well shame on me….lol

Can v get a video on the detection of the 1st star of our universe that was recordd recently

We demanded a Trebuchet video, and you delivered. Looks like I'm signing up for Patreon when I get home.

LOVE THE T SHIRT

Lol Great video ðŸ™‚ I made 3 trebuchet's for hacking the clock and the future ðŸ™‚ (and history (R)0fl what a blast , the internet , lol sending data over the the clock and the firewall ðŸ™‚ air resistance lol Clocks in Win CE hehe ðŸ™‚ Drivers are fun make ðŸ™‚ clock Bios "shots " lol

Isnt this bit too easy question? I mean its vacuum and that rock is free falling down

cool shirt

I have a question regarding black holes (I know it is very off topic but I lack the knowledge to figure this out). Say a space ship approached a black hole but did not cross the event horizon and kept a sizable distance. Now assume it "lowered" a cable with a tiny weight on the end (like a fishing line) until it just passed the event horizon. Assuming the cable had infinite strength and no weight besides the actual weight on the end, would the ship be able to reel in the cable or would the ship be spaghettified? Also, depending on the size of the weight and if it could be reeled in, what kind of forces would be required?

"Under the banner … Of Space Time"

Nice one !

Hi please can u do a video about the theory of the electrical universe. Why it is not accepted as a realistic theory, I am intrigued by some of the points of it, if not quite all. Thanks

Can u guys plz make a video on photo current and frequency relation ….m finding way different answers on internet….can u guys make a series on potoelectric effect…

AND HE DELIVERS! I was cackling like a madman when I saw the video this morning. Well played sir!

Do you sort or filter by subject line? You said sort but I believe that you meant filter.

Lighting ist bad this time ðŸ¤”

G'day,

Point 1), that would have to be the most condescending Scholar's Cradle ever posted to YouTube…(!).

Point 2), if the Bucket starts from the same height with both throws, launching Projectiles of equal Mass/Surface Area…, then it doesn't matter if the Projectile is launched early, climbs high, and then falls steeply – or if launched later and flies a flatter trajectory…; either way it begins with the same amount of Energy in the Bucket, so the Impact-Energy will be identical, regardless of the Launch-Angle, storing Kinetic Energy by converting it to Gravitational Potential via Altitude – & then reversing the Conversion by falling down….., doesn't increase or decrease the Impact Energy.

Such is Life…

;-p

Ciao !

Love you guys!

I love challenge questions where I can rely on my prior knowledge.Booooooooooooooooooring!

Made floating arm trebuchet for first semester physics, many regrets, math was FAR TOO advance for me…

I thought I clicked a video of T90Official

Vegeta what does the scouter say about his energy level?

did he just ask a high school level question?

So i have a sort of related question. If rockets are taking off and never really returning to earth, do we have to worry about changing the earths orbit?

How fast is the stone travelling AT the moment of impact … does he really mean just before impact or this a trick question ðŸ™ˆ

first one, at the top of its peak the projectile lost most of its velocity before it falls down. much shorter accerleration time.

I have a question regarding the extra credit question: does the projectile travel 300 meters upward (vertically) or do you mean that it travels 300 m towards the fortress (horizontally)?

Using a bale of weed going over drumph's wall would be funnier or Americans trying to escape!!

Submitted my answer I hope I win

Is it possible that sub atomic particles exist in more dimensions than just 3 or 4?

'that's the power of energy'.. whahh??!! energy has power now? But then, power is just a jar of energy spread over time toast.

Did… A video just make me do extra math homework?

what about floating arm, wheels, multiple rotations? ðŸ˜‰

but how does the trebuchet taste? …

All the other measurements are in metric so is the counterweight 5 metric tons = 10000Kgs? or 5 imperial tons = 10000 lbs?

I'm probably over thinking this…

"the trebuchet is a kind of catapult"

REEEEEEEEEEEEEEEEEEEEEEEEEE

Lol "That's the power of energy"

Probably not the best comment to make but, would you poke the proverbial dragon and do a video showing why planets are spherical in a way that someone who doesn't believe can not argue with almost reason? Sauce did a good job I know you can to.

There's a spread of flat earth people that's getting too big.

"PBS picks up on a dead meme and assigns homework questions"

This channel has honestly inspired me to go to school to become a physicist.

What if I convince a monk to scream "wololo" and convert the trebuchet into Christianity?

This video made me want to hurl…

Answer for the first question.

Shot with horizontal trajectory will cause more impact.

Shot with vertical trajectory will cause less impact because at a point in the air its velocity becomes zero and it starts to fall with aacceleration of 10 meters per second. It is no longer in influence with initial velocity given by the trebuchet.

please make a video on Hawking radiation

Gravity

Awesome sir

Did anyone catch what episode he was talking about a negative vacuum?

Who else would like to see some videos on m theory/string theory?

I just made one of those t-shirts.

if you made this video 2 years ago I would have do better on my trebuchet projects.

Spacetime fans stand to attention! And…fire!

What if the universe is a giant quantum AI where all the possible outcomes have and will happen, and we're all just a complex representations of 0's and 1's. Where evolution is just a complex form of compiled data. As a bonus to back up this hypothesis, the universe is cold and electronics perform best in cold conditions.

I'm scared

I'm going to be a stick in the mud and interrogate this entire preoccupation with classical physics. What is the point in doing exercises in classical physics, if classical physics is an emergent phenomenon of quantum mechanics?

Regarding the Treb as the greatest medieval siege engine: J.E. Gordon argues in 'Structures', that the treb had limited energy storage and low efficiency compared to the (then-forgotten) Roman ballista. Gordon claims the ballista was 10x more energy efficient, due to energy stored in its arms being re-transferred to the projectile, while most of the treb's energy was wasted in the arm/braking mechanism.

Question: say we discover a dark energy particle. Can we blow up a black hole by shooting dark energy particles into it, which ought to expand the space inside the Event Horizon?

Launching stones is nice and all, but everyone knows that a trebuchet needs to launch a pommel if you want to end them rightly.

You canâ€™t Trebuchet Chuck Norris, because his huge balls drag on the ground.

Chemists use conservation of energy in the form of Hess's law: the net change in energy from a reaction is always the same, whether the reaction is run forwards, backwards or with any combination of intermediate steps, as long as the start and end points are the same (same amount of starting reagents and end products). In biology this is important because the theoretical energy output from burning a lump of sugar is the same as digesting and metabolizing that same amount of sugar.

In other words, the law of conservation of energy says that humans are effectively the same as a forest fire.

https://youtu.be/GuwkbGAnkE0

question one, I believe from what I understand form the constant acceleration equations is that they will impact the wall with exactly the same force, neglecting air resistance and; moment of velocity in which they are released because the impacted at the exact same point therefor they most have the same v0, but this only applies if the height is equal at both points which I would infer that its. second question is pretty lengthy depending on the system of equations or the one equation that you learn at the end of physics 109 that teaches you everything you just learned in one equation, but because I'm tired at the moment ant wish to sleep the answer is M1 x 9.81 m/s^2 x the seconds that it is falling from the peak of the parabolic arc, neglecting air resistance.

This dudes speech pattern is about as exciting as watching a Ford rust.

My trebuchet answer was worked out in Chuck Norris Roundhouses per m2 per sec

Think itâ€™s worth doing an episode on this? https://twitter.com/nowthisnews/status/970940296191029248?s=20

Can you do an episode that explains what physicist mean when they talk about virtual photons??

I was just hoping to find out what those beams of 'pure energy' that Space Ghost shoots out of his power bands are really made of.

Solar Freakin Trebuchets! Make it happen someone. You dont even have to give me a percentage, I'm just giving that away for free.

Could you please do a video on ToE.

I dont get why people talk so much about string theory and not LQG. I came across this opinion which pretty much sums up most of my thoughts on , with the expection that I like the idea of a ER=EPR and the holographic principle.

The current picture of the Universe physics offers is that of interacting quantum fields. The theory of those quantum fields (i.e. the right QFT) is constructed by quantizing the corresponding CLASSICAL theory. Gravity is a field whose classical theory is general relativity (GR). So what should be done is to quantize general relativity. This is a challenging task, since general relativity (unlike other field theories) doesn't live IN a background; rather, the metric whose dynamics GR describes IS the background. This feature of general relativity is called background-independence. By switching to Ashtekar variables, the standard procedure of canonical quantization can be (and has been) applied to the GR Hamiltonian. The resulting quantum theory is known as "loop quantum gravity" (LQG). The theory (1) gives a model of the quantum geometry of spacetime, in which area and volume operators are quantized; (2) features background independence; (3) has been shown to reproduce the Bekenstein-Hawking entropy formula for all black holes (not just extremal ones as in string theory); (4) has been shown to have the correct semiclassical limit in various special cases (through the so-called Master Constraint Programme); (5) has been applied (albeit in the form of a toy-model) to cosmology, replacing the Big Bang singularity by a quantum "bounce". Current reserach directions include: (6) a purely combinatorial treatment of the dynamics (Algebraic Quantum Gravity) (standard LQG quantizes the metric but retains the continuum because the manifold is still used in the formulation of the dynamics; AQG is an effort to do away with the background manifold, hence the "purely combinatorial treatment"); (7) Checking that the theory reproduces GR in the classical limit; (8) the search for phenomenological consequences; (9) construction of a covariant formulation of the theory ("spinfoams"); (10) the possibility that unitarity is not lost in the process of black hole formation+evaporation; (11) the coupling of the theory to quantum matter.

Now that's the most promiment (although not the only) example of sensible quantum gravity.

Now, what about string theory? String theory starts as a (failed) theory of the strong nuclear force. When Quantum ChromoDynamics (QCD) was shown to be the correct theory of the strong nuclear force, string theorists realized that the formalism of string theory could be reinterpreted as the formalism of a unified theory of quantum forces including gravity. They were excited when they discovered that "graviton-graviton" string scattering was well behaved. Nonetheless, the framework had (and still has) a lot of problems, mainly:

1) it needs supersymmetry (SUSY) in order to be physically consistent. SUSY still doesn't show up, and has lost much of its initial appeal.

2) it needs a 9+1 -dimensional spacetime in order to be mathematically consistent. Since we live in a 3+1d world, the (entirely ad hoc) assumption had to be (and was) made that the extra 6 spatial dimensions are "compactified" at the Planck scale. Problem is, there are 10^720 different ways to compactify those extra spatial dimensions (in structures called "Calabi-Yau manifolds", corresponding to different "string vacua") and the physical predicions of the theory strongly depend on which one you choose. The solution to this problem? Hello multiverse!

3) it is a perturbative, background dependent framework, which means it assumes a flat background spacetime on which gravitons propagate. This amounts to a failure of taking seriously the main conceptual lesson of GR.

4) the formalism is based on Feynmann diagrams, which (at least to date) are not mathematically rigorous.

5) the theory is non-unique: there are five versions of perturbative superstring theory.

There is an additional problem of a sociological character, which is that string theory is mostly done by particle physicists, who rely more on heuristic arguments and "physical intuition" (whatever that may be) than on rigorous mathematical manipulations (often without even knowing this is the case, as happens for example with path-integrals), and who tend to be philosophically lacking and conceptually narrow-minded.

What Witten did is to give plausible arguments for what is still a conjecture: the existence of a nonperturbative, background independent, 10+1 -dimensional quantum theory involving not only strings but other extended objects of superior dimension (called "d-branes"), which would give the five different string theories and 11D supergravity (a unified theory candidate which was popular at that time, which basically was the result of GR + SUSY) as different limits. He called this to-be theory "M-theory".

Another important (and also still unproven) conjecture was the AdS/CFT Conjecture by Maldacena, which posits a duality between n-dimensional M-theory in an Anti-deSitter (AdS) spacetime and a (n-1)-dimensional conformal field theory (CFT) living in the boundary of such spacetime. What string theorists did was to act as if that was a proven conjecture, and then to make even bolder conjectures of increasing level of delirium, such as the "holographic principle", "spacetime from entanglement", "ER = EPR", "it from qubit" and the latest piece of schizophrenia by Susskind, "QM = GR".

So, at a theoretical level, M-theory doesnÂ´t even exist as anything else than a pile of unproven conjectures. Accordingly, superstring theory is not the leading candidate to a ToE (the leading candidate for Quantum Gravity would be LQG and the leading candidate for unification of the forces is probably ConnesÂ´s programme of noncommutative geometry in physics, particularly the Spectral Standard Model and the more general Spectral Pati-Salam Model).

And at a sociological level, the superstring approach is indeed the most popular one (although its popularity keeps declining) because we have too many high-energy physicists and so few mathematical physicists.

Conservation of energy doesn't account for the big bang

That t-shirt is awesome where can I get it?

E = mc^2

KE = 1/2 mv^2

Watching this video, this occurrence came to mind: I see interesting similarities considering that c IS a velocity.

It's interesting to me that when v=c, E=KE can only be satisfied if m=0, and, coincidentally, a photon IS mass-less.

(and, yes, I do understand that technically E=mc^2 is only completely true for an object at rest and so completely does NOT apply to kinetic energy, but the similarities in the equations IS interesting, nonetheless)

2nd shot does most damage. Mainly because of Gravity increasing its speed down. And because of the Force of Impact is mass X velocity wich is increased if you add gravity with it. 9.8M/S if the projectile is high enough it will reach terminal velocity and crush basicly anything thats below it.

(I didnt use any maths or what so ever. Just basic knowledge of gravitional pull. Feel free to correct me)

Trebuchet=time travel

I would've done it but I had too much dynamics homework to do

But if I'm playing as a Briton I get bonus splash damage with Warwolf… how do I factor that into my equations? Also, siege Engineers gives a bonus 20% damage to buildings once researched, so should I provide answers with this additional 20% included or assume the player hasn't got enough spare wood?

fuck fascist chuck norris

Wololo

Hmmm I wrote down the solution like 2 weeks ago (would've been still one week to send it in) and since then it lies around on my desk. What's wrong with me that I'm this lazy? xD

1st Q: The damage is the same in both cases. The amount of energy in the projectile does not change (no matter the trajectory) since only conservative forces are acting on the projectile.

2nd Q: If you want to skip the detailed proccess: V = 66[m/s] or V = 75[m/s] depending on assumptions.

2.1 – Find the âˆ†PE to determine how much energy was transferred from the counterweight to the projectile.

âˆ†PE = PE_1 – PE_2 = (m_c)*(g)*(h_1) – (m_c)*(g)*(h_1)

Where:

âˆ†PE = change in potential energy

PE_1 = counterweight Potential Energy at position 1

PE_2 = counterweight Potential Energy at position 2

m_c = counterweight mass

h_1 = counterweight height at position 1

h_2 = counterweight height at position 2

m_c = 5[ton] = 4535.92kg

âˆ†PE = 4535.92[kg]*9.8[m/s^2]*8[m] – 4535.92[kg]*9.8[m/s^2]*2[m]

âˆ†PE = 355616 [kg*m^2/s^2] – 88904 [kg*m^2/s^2]

âˆ†PE = 266712 [kg*m^2/s^2]

2.2 Then we can find the release velocity of the projectile with the Kinetic Energy equation (solving for velocity)

and assuming that all the Potential Energy lost by the counterweight went to the projectile.

KE = (1/2)*(m_p)*(V_r^2) = âˆ†PE

Where:

KE = Kinetic Energy

m_p = projectile mass

V_r = projectile release velocity

KE = (1/2)*m_p*V_r^2 = âˆ†PE

Solving for V_r

V_r = sqrt((2*âˆ†PE)/m_p)

V_r = sqrt((2*266712 [kg*m^2/s^2])/90[kg])

V_r = 76.99 [m/s]

***If the projectile would have been launched at the same height it crashed (either 0 or 15 meters), the problem would have ended here since the initial and final velocities would be the same in the "x" and "y" axis. But since there is a change in height, it means that there is a difference between the initial and final velocity in the "y" axis, although in the "x" axis it remains constant therefore the velocity vector has to be decomposed.

2.3 Separating the release velocity vector into its "x" and "y" axis components:

V_r = sqrt((V_r_x)^2+(V_r_y)^2)

V_r_x = V_r*cos(Î±)

V_r_y = V_r*sin(Î±)

Where:

V = Velocity vector

V_r_x = release velocity vector component in "x" axis

V_r_y = release velocity vector component in "y" axis

Î± = projectile release angle

V_r = sqrt((V_r*cos(Î±))^2+(V_r*sin(Î±))^2)

2.4 Finding the impact velocities in the "x" and "y" axis:

Assuming projectile release angle (Î±) of 45 [deg]; (since it wasn't provided in problem statement)

Assuming V_r_x = V_i_x (release and impact velocity in "x" axis is constant)

From section 2.3:

V_r_x = V_r*cos(Î±)

Therefore:

V_i_x = V_r*cos(Î±) = V_r_x

V_i_x = 76.99[m/s]*cos(45)

V_i_x = 54.44[m/s]

Using the following equation for the change in velocity in the "y" axis:

âˆ†V_y = -sqrt(2*(g)*(âˆ†h))

âˆ†V_y = V_r_y – V_i_y

where:

âˆ†V_r_y = change in velocity in "y" axis

âˆ†h = change in height in "y" axis = 15[m] – 0[m] = 15[m]

V_r_y – V_i_y = -sqrt(2*(g)*(âˆ†h))

Solving for V_i_y:

V_i_y = V_r_y – sqrt(2*(g)*(âˆ†h))

From section 2.3:

V_r_y = V_r*sin(Î±)

Therefore:

V_i_y = V_r*sin(Î±) – sqrt(2*(g)*(âˆ†h))

V_i_y = 76.99 [m/s]*sin(45) – sqrt(2*(9.8[m/s^2])*(15[m]))

V_i_y = 54.44[m/s] – 17.15[m/s]

V_i_y = 37.29[m/s]

2.5 Finally, for the impact velocity (V_i):

V_i = sqrt((V_i_x)^2+(V_i_y)^2)

V_i = sqrt((54.44[m/s])^2+(37.29[m/s])^2)

V_i = 65.99[m/s] â‰ˆ 66[m/s]

my question to you is whether your 'FIRST Question situation' is actually possible in a Trebuchet?? Can there be 2 release points that give away same amount of energy to the Stone when the initial release height is the constant?

Energy transfered into projectile = Potential Energy lose from counterweight.

Counterweight is 1m off the ground, the counterweight's maximum potential energy is at a height of 7m and finishes at 1m.

PE(start)=KE+PE(Finish)

mgh(start) = mgh(finish) + 1/2mv^2

(5000×9.8×7) = (5000×9.8×1) + (1/2x90xv^2)

343,000J = 49000J + 0.5 x 90 x v^2

KE = 294000J = 0.5 x 90 x v^2

v^2 = 6533.3333

v = 80.829m/s

basic highschool physics this.

Before anyone flames me, this is done weeks after the challenge. Cos I never watch videos on time anyways…

Even simpler, you could just do 5000×9.8×6 = 1/2x90xv^2. You don't even need to know the lowest point of the trebuchet counterweight. All you need to know is how high it rebounded to know how much energy it lost to the projectile. The trebuchet arch could be 20m and come back up to 14m and the answer would still be the same.

The trebuchet animation doesn't accurately show the motion of the counterweight. The reason counterweights are mounted on a rigid arm like that is that it lets them fall in a straight line for longer so when the throwing arm is vertical the counterweight should still be in front of it, tilted at an angle.

This is a great problem to demonstrate the power of Lagrangian dynamics and the Chaos concept using double inverted pendulum.

You play AOE too bro?

Trebuchets > catapults

Finally!!! Maybe now people will stop using the term energy wrong!

This is an invitation to see a theory on the nature of time! In this theory we have an emergent uncertain future continuously coming into existence relative to the spontaneous absorption and emission of photon energy. The future is unfolding with each photon electron coupling or dipole moment relative to the atoms of the periodic table and the wavelength of the electromagnetic spectrum. This is part of a universal process of energy exchange that forms the ever changing world of our everyday life.

The second shot will do the most damage . It's called plunging fire .

I feel like it would partially depend on what the exact target is. But if its only speed its neither of them or both of them. Both arcs are going to lose and gain speed at different degrees but find equilibrium. Also its travelling 0 speed at the moment of impact its released that energy into what I assume would be kinetic energy into the target.

108 people think catapults are the superior siege weapon.

Man when I was in High School, I built a bad ass trebuchet. The trick is having a fulcrum on wheels. I had a track for the wheels that was the fulcrum. The counter weight would fall straight down maximizing potential gravitational force.

BruceLee>ChuckNorris

anyone want me to spoil the answer coz its answered in a futurevideo

This guy's head doesn't match his body

Is this guy a vegan? He looks like a vegan

Nothing new. Stop making Videos on Basic School stuff. Come up with something new. This channel is a total waste of time.

no such thing as have or not, do , can do any nmw and any b perfect