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Physics Unsimplified
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Добавлен 17 янв 2019
Lectures on various topics in physics.
The primary goal of these videos is to help the viewer understand, not to (simply) entertain. Videos on topics like general relativity and classical mechanics assume a fair amount of mathematical skill and physics experience on the part of the viewer.
"Everything should be made as simple as possible, but not simpler" (quote often attributed to Albert Einstein)
---David Brown
In the interest of transparency: I'm a professor of physics at NC State University (in the eastern part of the US) with a PhD in physics from the University of Texas at Austin. All of the information in these lectures can be found in standard textbooks, or derived directly from standard results in those texts.
The primary goal of these videos is to help the viewer understand, not to (simply) entertain. Videos on topics like general relativity and classical mechanics assume a fair amount of mathematical skill and physics experience on the part of the viewer.
"Everything should be made as simple as possible, but not simpler" (quote often attributed to Albert Einstein)
---David Brown
In the interest of transparency: I'm a professor of physics at NC State University (in the eastern part of the US) with a PhD in physics from the University of Texas at Austin. All of the information in these lectures can be found in standard textbooks, or derived directly from standard results in those texts.
Perpetual Motion and Free Energy!
The overbalanced wheel has been proposed as a free energy/perpetual motion device. This video shows my own overbalanced wheel design
in action. In a follow-up video, I will explore the physics of overbalanced wheels and show why videos such as this one must be fake.
in action. In a follow-up video, I will explore the physics of overbalanced wheels and show why videos such as this one must be fake.
Просмотров: 15 841
Видео
NASA's Helical Engine and Other Reactionless Drives
Просмотров 33 тыс.2 года назад
Reactionless drives are spacecraft engines that produce thrust without any exhaust. Examples include the Dean drive, GIT thrusters, and EM drives. The latest proposal is the Helical Engine, described in a NASA technical report by David Burns. In this video I discuss the fundamental reason why reactionless drives don't work: They violate Noether's theorem which links spatial translation invarian...
Singular Lagrangians, Constrained Hamiltonian Systems and Gauge Invariance
Просмотров 1,9 тыс.2 года назад
Recording of a talk presented at the April 2022 meeting of the APS (American Physical Society). The topic is the Dirac-Bergmann algorithm, which is a prescription for converting a singular Lagrangian system into Hamiltonian form.
Chain Fountain/Mould Effect (Just Do the Damn Calculation!)
Просмотров 2,9 тыс.3 года назад
The chain fountain (or Mould effect) is fascinating and perplexing: a bead chain forms a fountain as it rises above the sides of a container before falling to the floor. The chain fountain was analyzed by Biggins and Warner in 2013-2014, but the explanation based on their work is still questioned. In this video I carry out a detailed calculation, equivalent to the one given by Biggins and Warne...
Physics of the Blackbird Wind Powered Vehicle
Просмотров 6 тыс.3 года назад
Blackbird is a wind powered vehicle consisting of a wind turbine linked to its wheels. Blackbird can travel directly downwind and upwind at speeds that exceed the speed of the wind. This counterintuitive result has been a source of controversy. In this video I use Newtonian physics to examine a simple model of a wind powered vehicle, similar to Blackbird. I compute the maximum downwind and upwi...
Gyroscopic Motion: Equations of Motion for the Two-Top
Просмотров 5 тыс.4 года назад
In the video ``The Mystery of Gyroscopic Motion: How Does It Do That?", I analyzed the physics of a simple spinning top constructed from two masses, called a ``two-top". I described in qualitative terms, and in detail, the forces that keep the two-top spinning and precessing. In this video I derive the equations of motion for the two-top using Lagrange multiplier methods. Simulations of the two...
The Mystery of Gyroscopic Motion: How Does It Do That?
Просмотров 62 тыс.4 года назад
Gyroscopic motion is both fascinating and mysterious. A spinning top seems to defy gravity as it executes gyroscopic motion. In this video I explore gyroscopic motion in detail by examining the physics of a ``two-top". A two-top is a simple top constructed from two masses held together by massless struts. The failure of our intuition for gyroscopic motion is traced to a subtle misinterpretation...
The Dzhanibekov Effect: Equations and Simulations
Просмотров 4,4 тыс.4 года назад
The surprising behavior of a rotating rigid body, known as the Dzhanibekov effect, is explained intuitively in the video "Rigid Body Motion and the Dzhanibekov Effect". Here I derive the equations of motion for the four-mass rigid body used in the simulations. The analysis uses the Lagrange multiplier method, which yields explicit formulas for the internal forces that hold the rigid body togeth...
Does the Falling Pencil Hit the Table? Equations and Answers
Просмотров 2,4 тыс.4 года назад
The following problem was posed in a video by Matt Parker, posted on his RUclips channel "Stand-up Maths": A pencil, initially sitting upright at the edge of a table, is knocked off the table with a kick to its lower end. Will the pencil hit the table as it falls? In this video I work out the solution in detail, and show that there are three possibilities: (1) For a large kick, the pencil misse...
Rigid Body Motion and the Dzhanibekov Effect
Просмотров 29 тыс.4 года назад
I give an intuitive explanation of the Dzhanibekov effect on a rotating rigid body, and discuss its relationship with the intermediate axis theorem. Simulations were created using glowscript (glowscript.org), developed by David Scherer and Bruce Sherwood. The simulations are based on the Lagrangian equations of motion for a simple rigid body. I will present the mathematical details in an accomp...
Differential Forms, Integration and Stokes' Theorem
Просмотров 4,6 тыс.4 года назад
Beginning with the primitive theory of integration of differential forms, I show how integration is defined on a manifold with metric using the natural volume element. I then use Stokes' theorem to derive the curved spacetime version of the divergence theorem. Examples include conservation laws in general relativity, and the result known as Stokes' theorem in electrodynamics.
Multiple Black Hole Zoom-Whirl Orbits
Просмотров 6324 года назад
Simulation of multiple zoom-whirl orbits around a Schwarzschild black hole. (Each orbit is type (2,1,1), using the syntax of Levin and Perez-Giz, Phys.Rev.D 77 (2008) 103005.) The simulation was created in python using glowscript (glowscript.org). Air Hockey Saloon by Chris Zabriskie is licensed under a Creative Commons Attribution license (creativecommons.org/licenses/by/4.0/) Source: chriszab...
Black Hole Zoom-Whirl Orbit (4,1,3)
Просмотров 8244 года назад
Simulation of a satellite orbiting a Schwarzschild black hole in a zoom-whirl orbit. The elapsed time for this orbit, assuming a one-solar mass black hole, is 0.018 seconds as viewed by a stationary observer at infinity. The elapsed time on the satellite is 0.016 seconds. The arrow represents the satellite's spin, which is parallel transported along the orbit. (This orbit is designated (4,1,3) ...
Black Hole Zoom-Whirl Orbit (2,0,1)
Просмотров 1,3 тыс.4 года назад
This is a simulation (not an animation) of a test body orbiting a Schwarzschild black hole in a zoom-whirl orbit. The orbit type is designated (2,0,1) in Levin and Perez-Giz (Phys.Rev.D 77 (2008) 103005 • e-Print: 0802.0459 [gr-qc]). The simulation was written in python using the glowscript web-based environment for 3D modeling. The primary developers of glowscript (www.glowscript.org/), and it...
Black Hole Zoom-Whirl Orbit (3,0,2)
Просмотров 8524 года назад
This is a simulation (not an animation) of a test body orbiting a Schwarzschild black hole in a zoom-whirl orbit. The orbit type is designated (3,0,2) in Levin and Perez-Giz (Phys.Rev.D 77 (2008) 103005 • e-Print: 0802.0459 [gr-qc]). The simulation was written in python using the glowscript web-based environment for 3D modeling. The primary developers of glowscript (www.glowscript.org/), and it...
Einstein Hilbert Action (General Relativity)
Просмотров 15 тыс.4 года назад
Einstein Hilbert Action (General Relativity)
35. Gravitational Waves VI: More About Sources (General Relativity)
Просмотров 1,6 тыс.4 года назад
35. Gravitational Waves VI: More About Sources (General Relativity)
34. Gravitational Waves V: Sources (General Relativity)
Просмотров 1,7 тыс.5 лет назад
34. Gravitational Waves V: Sources (General Relativity)
33. Gravitational Waves IV: Energy and Momentum (General Relativity)
Просмотров 2,9 тыс.5 лет назад
33. Gravitational Waves IV: Energy and Momentum (General Relativity)
32. Gravitational Waves III: Linearized Gravity and Gauge Conditions (General Relativity)
Просмотров 4,7 тыс.5 лет назад
32. Gravitational Waves III: Linearized Gravity and Gauge Conditions (General Relativity)
31. Gravitational Waves II: Interferometer Detection (General Relativity)
Просмотров 1,9 тыс.5 лет назад
31. Gravitational Waves II: Interferometer Detection (General Relativity)
30. Gravitational Waves I: Introduction (General Relativity)
Просмотров 8 тыс.5 лет назад
30. Gravitational Waves I: Introduction (General Relativity)
29. Cosmology III: The Big Bang and Inflation (General Relativity)
Просмотров 2 тыс.5 лет назад
29. Cosmology III: The Big Bang and Inflation (General Relativity)
28. Cosmology II: The Friedmann Equation (General Relativity)
Просмотров 6 тыс.5 лет назад
28. Cosmology II: The Friedmann Equation (General Relativity)
27. Cosmology I: Isotropy and Homogeneity (General Relativity)
Просмотров 3,1 тыс.5 лет назад
27. Cosmology I: Isotropy and Homogeneity (General Relativity)
26. Rotating Black Holes and Aspherical Collapse (General Relativity)
Просмотров 1,8 тыс.5 лет назад
26. Rotating Black Holes and Aspherical Collapse (General Relativity)
25. Gravitational Collapse and Black Holes (General Relativity)
Просмотров 4,1 тыс.5 лет назад
25. Gravitational Collapse and Black Holes (General Relativity)
24. Black Holes (General Relativity)
Просмотров 2,3 тыс.5 лет назад
24. Black Holes (General Relativity)
23. Schwarzschild Solution and Stellar Models (General Relativity)
Просмотров 2,4 тыс.5 лет назад
23. Schwarzschild Solution and Stellar Models (General Relativity)
22. More Stress, Energy and Momentum (General Relativity)
Просмотров 1,9 тыс.5 лет назад
22. More Stress, Energy and Momentum (General Relativity)
6:33 is the helical engine diagram
Light carries momentum. When a body at rest is hit by light momentum is transfered from the light to the body.
sir link is not working for download the slides. can you please provide slides🙏🙏🙏🙏🙏
Horrible expliplination and is wrong btw, a propelled airplane breaks the conservation of energy law bc it is manipulating its environment in order to move
awesome explanation. thank you so much for taking the time to share
52:00 Covariant derivative of a vector field by parallel Transport
6:22 Basis vectors of polar coordinates are different at two different points
8:15 Parallel Transport
12:40 C contains info of how the basis vectors change due to parallel transport from point Q to point P. 16:10
21:12 Christoffel Symbol involves C. I see that we still don't know how the basis vectors change due to Parallel Transport.
23:20 interpretation
So there's two centripetal forces acting, one pulling the top together so it won't separate, the other is radially pulling the top as one mass towards the sphere. And due to gravity being one-directional, these two interact differently. At half of the phase they move against gravity, and at another they move with gravity. This results in it favoring a certain direction on the sphere for the system to precess on. If this is true, then I believe dictating the direction of the top's movement around the sphere, in this case right-hand-ruling normal force of the system, is putting the cart fore of the donkey. I believe that it does favor a direction, because I tried spinning a pendulum out of a rope and duct tape with my right arm clockwise relative to my eyes, and it is easier to slowly spin my whole body on the y axis to the left than it is to the right. If I tried doing it to the right, usually the pendulum doesn't want to follow my arm, and gets close to the front of torso instead.
Here’s a potential hint from this layman: Casimir effect conveys what is occurring here.
Could you give me the bibliographical references that were used in this video?
Your series are seriously badass!
The solution to this problem is in this video 'How Basic Electromagnetic Propulsion Works Without Ejecting Fuel' ruclips.net/video/vicR7dbb8Us/видео.htmlsi=32m0CHI165_sQeP0
The real reactionless propulsion going on is the propulsion of intelligent men to build fancy machines that don't produce useful work (other than vibrating back and forth), much to the delight of women everywhere.
Imagining the struts as springs also helps. When a red ball of a two-top is falling downwards, it is causing a compression in the radial strut/spring, hence a pushing force from that spring which acts outward. When a red ball is moving upwards(due to it's disk type rotational motion), it is causing the spring/strut to stretch and hence a pulling force from the spring which acts inward. I wonder what happens to Positronium rotating like a disk and then an electric field is switched on parallel to the axis of rotation.
I think the first part is wrong: xcm is not (i/m)t but it is proportional to t^2. You started from m*d/dx(xcm)=i and then you integrate respect to time forgetting that i is not constanct respect time since i=Ft so when you integrate you have: xcm=F/m*(t^2/2)
The principle of NASA's Helical Engine work , and it works very well, here is the proof ruclips.net/video/VXS56lRwrys/видео.html
How does Noether's Theorem explain time differences in a closed system on earth, in empty space or at a black hole's event horizon?
For a discussion of why the helical drive will not work, see m.ruclips.net/video/yNro9yiVZno/видео.html
Okay but you barely explained going frok one step to another
So from where momentum comes in Casimir effect? There are many things we do not know ...
Question ● have any of these drives been tested in the vaccum of space ?
they won't work? Even though objects are seen working.and are filmed?
Do you happen to have an INTUITIVE explanation for the Intermediate Axis Theorem? Feynman said "No." And my teacher and Einstein always said that if they can't explain it in common sense terms to the laypersons then chances are that they don't know what they are talking about.
Дятел ! ... здесь нет даже разницы перевеса грузов ( на 9 .00 и на 15.00 ) ! )) и даже малейшей попытки его нарушить .. !
You forgot about Russian engineer Tolchin
We want to go to America for families and friends and relatives and clans please help me with the issue
Gerak rotasi gasing Terhadap vertikal simestris jadi gaya gaya yg dihasilkan juga simetris,akan tetapi gravitasi hanya bernilai positif ke arah bawah sedangkan untuk ke arah atas negatif... Jadi bagaimana anda menerangkan hal ini???
I gotta let you know that there's other RUclipsrs that are 🤏 close to free energy; really! And their NEXT build iteration will achieve it, they absolutely promise.(That is, if the blackhats finally stop sneaking in their house at night and sabotaging everything).
If there’s some kind of drag, in the component of x axis, there’s a way… I know u can’t see that, maybe you can make extreme examples. Maybe it will work, but get insane hot due to dragging. Dragging on one direction, reducing drag on the other. Maybe work for 1 second and wait 1 year for the dragging to disperse? And where the energy comes from? Better use solar wind as they already exists or some super heavy elements with large enough mass that neutrinos can interact with…. Get creative, be creative! ❤there no such thing as “empty space”
Well explained. If you take the cyan to be the equator and the red to be the north and south poles, , based on mass one axis heavier than the other, applying this rule to the earth, can you predict the period of time where the flip would occur. Does this e plain the Younger Dryas and the cataclysm described in the book ADAM & EVE? It would also seem to suggest that there could have been previous civilizations on the earth which have been completely wiped away. Exceptions being the pyramids and the Richat structure where seems remarkably precise measurements for the foundation of the city of Atlantis. Would we feel the earth wobble as the poles moved while the impending flip approached?
Why isn't this used to explain atomics theory, as the energy and electrons are more or less correctly alligned... I found if we change some views this is the level of small this might function on. The way I see it is as Molecules become larger the oscillation frequency gets larger.... It's not as though they are spinning physically but the atoms at that level always are? In a state of energy due to gravity! So what then and does anyone else think as I do? Interested to hear others opinion
Can't work. Tell that to Klacktar.
So called yellow color impossible to see
Brilliant and certainly facinating!! I enjoy this video and the excellent explanation, description and awesome visual example of the Dzhanibekov effect.
I've watched this video so many times to review the subject. Thank you for making it!
That was a nice theoretical lecture of momentum conservation. But: all our equations are based on experimental observation. So: Did anyone try it out in real life? Did anyone really build it? You can not for sure say ""it can not work"", if you even did not bother to try it. I know, it might be a waste of time and money, but hey, so many useless things were already founded in the world, (like gender equality nonsense etc.) , so why not settle this thing once and for all with some experiments...
хорошее видео- показывает как объект неправильной формы пытается найти равновесие и выбирает алгоритм поиска, но как только исчезает точка крепления, нивелирующая всё многообразие центров тяжести, возникает ХАОС, назовём его -Простейший хаос, потому что природа, в отличие от человека, всегда ищет простейший путь. и находит его, а человек , видя это, решает, что систематизировал ,, кувыркание,, предмета неправильной формы. Золотое сечение всем в помощь😎
Nice explanation, but the missing frames in the animations made my brain twitch! - LOL
I love this! Great series!!
Explain inertial drive then. Can you? If you give a serious response maybe I'll try to explain.
I don't understand how an isolated body of mass can be "rotating". Since the body is isolated, it has no reference point to which it can feel its rotation.
god damn your voice is annoying
See that’s the old way of thinking that something has to be shot out to go forward. There is other ways specially if you can create gravity fields. And let’s not forget the EM drive was tested successfully too so call it impossibly all you way it’s your understanding of conversation of momentum that’s wrong not the test results.
Can you provide solutions for the probset you gave? Thank you.
What do you think about Dr. Charles Buhler and your propellantless propulsion?
The professor was right. If he was wrong then the vehicle should keep traveling when no wind is present after an initial push. There should be a chart where at wind speed of 1 mph the cart moves at 2.7 mph, at 2 mph the cart moves at 5.4mph and so on. But this chart will never be made because it brakes the 1st law of thermal dynamics. As for the treadmill test is ludacris!if anything it is simulating a head wind. this should be able to chart on a graph as well. What do you think will happen when the treadmill goes at a walking speed? The answer is nothing will happen. To really test it they should take the most optimal small scale modle that they have created, make a wind tunnel the length of a football field where every bit of air in the tunnel flows exactly the same speed (as close as possible), have multiple readings take place throughout the tunnel to get average wind speed and then set the unit down and see if it can beat the average wind speed th get to then end. But it can't and won't. It would be cheaper to build this than that large unit but they can fudge the numbers with the large unit how fast should it go at 1mph, 2mph, 3mph. There should be a graph charting this. Wind tunnel and unit on a track is the best way to test. Keep it small like the treadmill units. Have steady wind speed. But this won't happen because it would ruin the theory. If it runs faster than the wind @ a wind speed then it should be able to run faster than the wind at 0 mph. Let me explain: If it's the wheels powering the propeller which pushes the vehicle faster than the wind then after starting the unit with a push the wheels should be able to power the propeller and push it at the same rate as when it has wind. A vehicle moving at 11 mph with a 10 mph tailwind is moving upwind at 1mph. The wind in perspective to the vehicle is now a head wind. A vehicle traveling 1 mph in no wind has a 1mph head wind. It's the same thing. Get the vehicle started with a push and it should beable to power itself. I don't think I'm missing anything but if I am please explain just rewatched the blackbird professor bet video. @12:05 the claim is made "the propeller thrust force is greater than the drag on the wheels". If this statement is true we can expect the unit to produce greater thrust force in a no wind test. Just get the vehicle started with a push and then the propeller will overpower the drag that wheels produce Im not into all the math equations but just coming from a practical standpoint imo the black bird is a hoax
The energy is coming from the ground and wind speed differential. 10mph vehicle, 10mph wind, 0mph ground is equivalent to 0mph wind, 0mph vehicle, -10 mph ground. In fact this exact scenario is shown with the treadmill demonstrations. The vehicle doesn't require wind, just a difference in airspeed and groundspeed.
As for where the energy comes from, the propeller can hit wind particles from the correct direction even when the cart is going faster than the wind.
Can you make a video on calculating bending angle by gauss bonnet theorem
This is so beautiful. No wonder Rutherford said everything else is stamp collecting
I doubt single perpetual motion will works but.. i think multiple engine perpetual motion will work no doubt.. because they sharing forces with each other ❤
You are absolutely right
Physics Unsimplified , you are 50 years behind. My question is , what would someone pay for it? It is very real.
There is absolutely no need for new physics or breaking any known laws. Here's a breakdown of how this concept works in terms of energy conservation: Energy Input: The onboard power generation system produces electrical energy continuously. This energy can come from various sources, such as advanced solar panels, nuclear fission plants, or hypothetical future technologies. Acceleration of Mass: The electrical energy generated by the power system is used to accelerate a mass, such as molten iron, into a circular path. This can be achieved using electromagnetic or mechanical means, depending on the specific design of the propulsion system. Circular Motion: As the mass enters the circular path, it experiences centripetal acceleration, which causes it to move in a circular trajectory. The energy required to maintain this circular motion is supplied by the onboard power system. Directional Thrust: By strategically directing the circular motion of the mass and then abruptly changing its trajectory, the system can produce a directional thrust in the desired direction. This change in momentum results in forward propulsion of the spacecraft. Energy Conservation: Throughout this process, the energy input from the power system is converted into kinetic energy of the mass and redirected as thrust to propel the spacecraft forward. Since energy is neither created nor destroyed according to the law of conservation of energy, the total energy of the system (including the kinetic energy of the mass and the electrical energy from the power system) remains constant. In this propulsion concept, the energy input from the power system is indeed preserved and converted into kinetic energy to generate thrust. The key challenge lies in the efficient transfer of energy from the power system to the mass and in controlling the direction and magnitude of the resulting thrust to achieve effective propulsion. Additionally, practical implementation would require overcoming engineering challenges related to materials, efficiency, and system reliability. This would work because of conservation of momentum and this is not like some proposed drives a case of trying to accelerate the car by pushing the backseat ... or even simpler ... I stand on a platform in space and throw a mass out in front of me converting power into kinetic energy. I have tied a rope into the mass and when the rope is tight the mass of the platform will through the rope try to break the motion of that mass, which it of course will, but some of the energy will pull on the platform and change its momentum. We will start to drift in the direction of the pull. We convert one type of energy into another, and end up with motion. This is not even something I would need a physics lab to show. Stand on a skateboard and hold a mass in your hands, then fling that mass outward while holding it. Conservation of momentum will set you in motion. Continue to do so and for each time you fling out the mass you accelerate since you create more kinetic energy. Actual results from a simple experiment, and if your calculations show otherwise then it isn't because I break any laws of physics, but because your calculations does not hold up with reality.
Your platform scenario doesn't work exactly by conservation of momentum. It applies at the start, too. When you throw the mass one way, the platform will start moving the other way. When the rope gets pulled taught this effect will cancel and the platform and the mass will stop(in the original rest frame).