Classical Physics

I'm trying to come up with an analog gravity model based on my old experiment. It's in the picture above. It's a vibrating boat on the water. In the center is a motor, on it is a pendulum with a magnet. A rod with another magnet is rigidly attached to the motor from below, the poles of which are opposite to those on the pendulum. This gives a temporary acceleration to the pendulum when it passes the magnet, and as a result, the system oscillates asymmetrically. All this is installed on a float and launched into the water. The resulting force of asymmetric oscillations creates thrust when the hull interacts with water. Hydrodynamics is a separate topic here. In shor…

Hi Guys, I am diving into the working principle of a Coriolis mass flow meter. I do understand how the mass flow is calculated and how the Coriolis principle works in theory based on rotating systems. The problem I encounter is that I can't match the theory with the practical application. The theory describes the force on an object in a rotating system that makes its path bend. But what is the initial cause for the bending of the tubing in the image underneath? (green arrow force) Is it the medium that shifts direction into the tube? Thanks

Hi all, this is my first post on the forum so please be nice. I have been contemplating a device that is remarkably simple but, at least to me, somewhat curious. We all know that if we bring two like magnetic poles together they will repel. Equally, if we insert a sheet of magnetically permeable material in the space between the repelling poles they will attract to the sheet. Please examine the above drawing (sorry it is just a rough sketch). On the left is a metal rotor that has slots cut in it so that it resembles a disc with metal fingers around the periphery. When rotated the fingers pass between the two opposing magnets that are fixed to levers. T…

Hi everyone, I am studying thermodynamics, and I'm confused about item b. I understand why the professor used W = 0 since Pexternal = 0; however, I'm unsure why Delta T also equals 0. Should I consider that process B is also isothermal, or is the phrase "an isothermal reversible expansion" only applicable to item c? From what I recall, an expansion for Pexternal = 0 does not necessarily result in a Delta T = 0, or it does.

We have a essay research and i can not choose the subject.Could you please help me?

I recently learnt the rocket problem: how to derive rocket equation. I accidently saw the problem about the force that is exerted on rocket part (rocket and unused fuel). My problem is: F(t) fore force that is exerted on rocket part (rocket and unused fuel) at time t should be F(t)=mdv/dt+vdm/dt, where m is the mass of rocket part at time t and v is the velocity of rocket part at time t, according to F=dp/dt=mdv/dt+vdm/dt which is true as the foundation of established physics, right? If we use the velocity function with respect to mass derived from the rocket equation v=v0+ve*ln(m0/m) and assume rocket expels gas mass at a constant mass flow rate R: m(t)=m0-…

To create faster and more economical internal combustion engines, I propose to use my invention - Riyanov double-slider crank mechanism (Two-slider crank mechanism). I received 4 patents in Russia (№ 2634851), China (№ 3349271), Japan (№ 6373516) and the UK (№ 3530879) for my invention, which can be used to create more environmentally friendly and faster engines, generators or in other projects. SUBSTANCE: crank double-slider mechanism includes a crank, two connecting rods and two sliders. The second connecting rod is connected to the first slider at one end, and to the second slider at the other end. The second connecting rod length is equal to the sum of the double…

Is this resolution wrong? Since the value of Wad is -4.68 KJ, applying this value to the expression ln(pi/pf) should yield a positive result of 0.750 instead of -0.750, correct? This is due to the minus sign in the equation.

Lamentable Lagrange Articles The Lagrange points are one of my interests. I am a little obsessed with the Earth Moon Lagrange 2 point. One of my pet peeves are wrong explanations of these five locations. So many articles and Youtube videos claim these are locations where gravitational forces cancel each other out. One of many examples is Fraser Cain's video What Are The Lagrange Points? Finding Stable Points In Space. From that video: People often sensibly ask about L2 and L3. At both these locations the central and orbiting body both pull the same direction. How do those cancel each other? Or at the L4 and L5 where the gravity vectors are 60º fro…

I try to calculate brake force for a primitive eddy current brake. The idea is that when a magnetic flux passes through a conductor (copper tube), it excites eddy currents, which are the source of the magnetic field, which is oppositely directed with respect to the external field, thereby generating a braking force. I found the equation for the braking force, which is calculated through power losses, and derived the expression for power losses. But I don't know how to determine the frequency (а) for calculating the skin effect (б), because I use direct current (eddy currents are excited by a quasi-alternating magnetic field). I also can't decide what to use as the char…

Hello! There was a question about the maximum stretching of the rubber band. For example, the Oxford Textbook provides a graph attached below. Can someone share if there is a more detailed schedule? Does the fluidity begin there? Or is it just tearing up? What is the stretching limit? And can we say that tga with line is Young's module at a given tension?

In spite of being age 29 I struggle to ask any woman out for a date because I can’t fully settle on a confidence level between a welfare applicant and a posthumous noble prize winner! Perhaps I shouldn’t even need a date to marry someone! One way to take Einstein’s relativity theory literally is that we might not be able to distinguish the vertical and horizontal directions apart in absolute space. As such we could theoretically rotate the solar system as moving in the vertical rather than the horizontal direction relative to a perpendicular galaxy. This way the oval shape of the Earth could be viewed as spinning vertically on its elongated axis rather than sideways on it…

I have found there is a common assumption that a big asteroid hitting would be worse (like the dinosaur one) than the same mass and speed of much smaller ones hitting and mostly burning up/exploding in the atmosphere before reaching the ground. In terms of heating up the atmosphere to an unlivable temperature, are they any different? I would think a given mass moving at a given speed would impart the same kinetic energy to Earth and its atmosphere regardless of whether it was a big one or an equivalent mass of small ones hitting at once. If the small ones would do less damage I am curious why, since the total kinetic energy should be the same. In other words would…

Hi, A superfluid has zero viscosity. If a vortex is created, it can rotate indefinitely without any loss of energy. There are objects less dense than a superfluid that can float on its surface, where a magnet can be placed. If a vortex is created in this liquid, the magnet will move indefinitely. If a bulb is placed in a closed circuit next to a moving magnet, the bulb will light up through electromagnetic induction. Here, the purpose of these questions is to understand why the bulb does not always light up through electromagnetic induction, even if the magnet moves indefinitely due to the vortex properties of a superfluid... What is the behavio…

This is more likely a question in biophysics but there's no such category in the forum and I (probably mis)judged it best to post in the physics forum. I remember holding a very small metal ball bearing in my palm and feeling its weight, heavy I thought. Then on another occasion I recall holding a piece of wood in my hand, light. I know that its weight, dependent on mass, that we sense. To be held up we need to exert muscular force and we feel the strain in our muscles. I was just thinking about this a while ago and realized that the ball bearing being spherical has a smaller area of contact with my palm compared to the chip of wood (flat). Immediatel…

If the hard problem of consciousness is at risk of taking another millennium to resolve then we might have to take the nuclear option! According to idealism where the world is only consciousness then in theory the mind could somehow survive a nuclear detonation for an afterlife. So one way to think of slow-wave sleep is like nuclear fusion where each half of the brain shares ideas in one timeline. Then REM sleep might resemble nuclear fission where each half of the brain disentangles from the corpus callosum to form independent ideas in two simultaneous timelines. That way a subsequent slow-wave sleep would merge the ideas formed during REM sleep to recursively knock us f…

Context: I am trying to educate/inspire two of my grandchildren but first I have to re-educate myself! A spacecraft arrives at above orbital speed with a nose first attitude and fires a retro-thruster when tangential to a circular orbit. Taking a simplified case, it used instant de-acceleration to orbital speed and therefore entered into a circular orbit. Would the following be true? As the spacecraft has no rotational forces acting on it, it would staying pointing basically at the same very far point, and to leave the orbit tangentially at another point, it would need to rotate itself to align its main thruster. If it used thrusters to give it a small rota…

I'm writing a short SF story about first contact with ET (a hackneyed subject for sure). Still, everything has come to a juddering halt due to a problem about large-scale laser communications within the solar system, more particularly a laser com setup located on an asteroid in the Belt. The problem is to do with laser receivers, or detectors, as they're also called. I understand the basic technology behind them, but can't picture what one would look like in the flesh. Surely it wouldn't resemble a giant radio dish? (like the one at Jodrell Bank, for instance). Instead, images of antennae keep popping into my mind. I have no idea why. Apologies for the dumbness of this qu…

Say I have created a strong enough micro and ir radiation source from a certain direction. I want a mini photocell/sensor to detect it. I know there are many mini photo diodes, etc available and cheap. But I need the sensor to be directional, having only one face to detect the radiation. If I flip the face, there would not be radiations detected. Also it should be easy to use, say just two leads to detect voltage/current. Also, what electrical instruments do I need to detect a voltage/current. Can a common multimeter do the job.

Guys, why in this question did the question answer only perform the product between area*P to calculate the mass? Question: Answer: Shouldn't the mass be calculated as m = (P*A)/g? Considering that: P = F/A, since: F = m*g P = (m*g)/A P*A = (m*g) m = (P*A)/g By performing dimensional analysis, you can indeed arrive at the value and unit: 2900 lb. However, I don't understand why gravity wasn't considered.

Do free neutrons attract, repel, or ignore each other?

Hello, I had a hiccup in explaining how sound is produced when materials break down. For example, A) we are tearing paper, B) we're unwinding duct tape. There is a break in the adhesion bonds. The breakage results in a sudden release of energy, which is converted to kinetic energy in some way, creating sound. How does sound occur? What's vibrating in there to cause it? I'm interested in physical part of production of sound in these processes.

It's often mentioned that cosmic rays include non-charged subatomic particles like neutrons as part of their mix. This seems to contradict the two facts that an isolated neutron spontaneously decays within just 15 minutes and that the universe is awfully big. The only solution that springs to this mind is that extreme time dilation (due to near-lightspeed motion) hugely extends a neutron's normal existence, relatively speaking. Is this true? Or is this a classic instance of not seeing the elephant in the room? 🤥

It is commonly stated in QM that a bound electron may only absorb a photon if only there is a matching energy gap difference that matches the photon energy. This seems ridiculous. Say a photon emitted by a hydrogen atom with the typical red emission frequency of the Blamer series. If this photon meets a piece of copper, it is unlikely that a copper atom has an exact matching two energy levels matching that of the Balmer spectrum of hydrogen. The photon would just cruise through copper without being absorbed. Well, if a statement is flawed, we then decide to "patch up" our theory and say there are other means that a photon may be absorbed by matter. So the scient…

If the voltage across a long wire is constant, is the current uniform throughout the wire length. In a 50 Hz ac voltage across a long wire, at a certain moment how does current vary along x, the wire length.