Classical Physics

Picked up some Ikea Dioders Led strip type. Any idea why multiple connectors in series would cause downstream lights to be a different color and if this could be utilized without decreasing the lifespan of the lights? Was thinking maybe due to increasing resistance. After some reconfiguring did get them working nicely for bias and under couch and bed lighting.

Hello everyone,, So I recently finished my BS in physics. Classical mechanics was by far my favorite subject . Is there any place for this kind of stuff in physics nowadays? It does not seem like it to me (there is some stuff with chaos and nonlinear dynamics). Also, I definitely want to go to grad school, but afterward I do not see myself going into academia (maybe not a research career at all). I want to work with modern defense and/or space technology in some way, likely on the R&D side of things. All of this makes me think physics is not the place for me and that my interest in classical mechanics and aerospace and defense technology would be more at hom…

Late night thunderstorm - lightning appeared to hit less than a few hundred feet from house. Immediate effect - light in hall (ordinary bulb dimmed) went out, although electric power was still on (electric clock still working). Ten minutes later light in hall comes back on. How can an ordinary light bulb behave this way?

Hi all, I've got a question about crystals and crystal oscillators. I want to build one from a uncut piece of quartz crystal. Let's say 1x1x5 cm. A bit bigger or smaller is all fine but no millimeter thin plate of cut crystal. I understand that for a reliable crystal oscillator quartz plates need to be thin and cut at specific angles, but I don't care what frequency it has, I just want it to do something. Either create a measurable frequency or vibrate measurably. Would this be possible at all? Can you get any frequency data from an uncut raw piece of quartz? So far I've tried connecting a crystal with 2 electrodes on it to a frequency tester but no resul…

How does this relate to the conservation of angular momentum. The picture attached.

Hexagonal pattern works well for surfaces (2D). However in 3D I wonder what kind of "hexagonal pattern" it really is. The "chicken wire" pattern shown in Wiki is a mix of hexagons & pentagons.

Is it higher porosity and smaller size of pores which are responsible for much higher energy density of supercapacitor vs. electrolytic capacitor? Or there is something else? On other hand electrolytic caps are able to withstand much higher working voltages what suppose to contribute to energy density.

I am trying to break the law of conservation of momentum, and design a mode of transport through space without using a propellant. I know most people will stop reading now and say it can't be done, but if somebody could at least explain what is wrong with my logic I would appreciate it. Propellant less space engines using relativistic mass. Method 1 – Shotgun The engine is basicaIIy accelerating two “cannon balls” down twin barrels and then stopping them before they reach the end of the “spaceship”. Before we fire them we spin them to a high speed so they gain a portion of relativistic mass, then we stop the spinning during the journey down the barre…

Hello Friends, I have been wondering, is it possible to construct a motor, and attach a coil to it, such that with the motion due to the rotation of the motor, it generates a excess of energy that can be used to power the motor in turn, basically, could i use the excess to charge a battery that then is used to turn the motor. Short of doing the calculations i am honestly not sure.

Suppose we have an experimental set up where there is a set of mirrors parallel to each other and two beams of light are set off bouncing back and forth in between and perpendicular to them for an extended period. At first the two beams are aligned parallel to each other. Can it be shown that these two beams will always always converge when any effects of gravity are allowed for? If this can or has been experimentally confirmed does it show that there is no such thing in Nature ( the physical world) as the Euclidean idea of parallel lines?(only approximations) Or might there be other ways of attempting to reproduce …

It is claimed that Schottky type of contact between low work function p-type semiconductor and higher work function metal creates an ohmic contact in which current can flow both sides almost fluently with very low resistance. It is also claimed that electrons have tendency to flow (when no potential is applied) from low work function material to higher work function material. So, when low work function p-type semiconductor comes in contact with higher work function metal, a p-type semiconductor will not let electrons from metal enter into semiconductors and will push them back. It seems a bit counterintuitive to me, because how in this case could it be an ohmic contact? D…

Hi, does anyone have an idea of the amount of static charge (in Coulombs) that is transferred to a balloon ( 20 cm in diameter) upon rubbing it with wool ? I know it depends on all sorts of factors, how I rub, etc., but I'm just looking for an order of magnitude. Thanks, McCrunch

I have two scenarios. One; imagine that, at the same time as the engine of your ship is ignited, there is also a device detonated inside the ship. If timed correctly, the difference between the two would equal out, right? For now, there's one huge problem and that's making sure the aim is correct, because, if you collide with an asteroid or something, you'd just spin out of control, but if you could measure the trajectory perfectly, there would be nothing in the way of that, if space, truly, is a vacuum which could accommodate fast travel. Next, there's the slowing down. Once the blast has burned out, you would naturally slow down, but the process of slowing down an o…

Some sources claim there is a substantial band gap between valence and conduction bands in monovalent metals. It might be associated with half-filled zone. Is it true or not? If it's true then why they are still metals and not a semiconductors? Fig.2.2.10 Possible energy band diagrams containing one filled or partially filled band and one empty or partially empty band. Shown are a) a half filled band, b) two overlapping bands, c) an almost full band separated by a small bandgap from an almost empty band and d) a full band separated by a large bandgap from an empty band. https://ecee.colorado.edu/~bart/book/eband3.htm http://www.schoolphysics.co.uk/age16-19…

The energy density of an electromagnetic field with a linear dielectric is often expressed as \(0.5 E \cdot D\). It is also known that energy can be found by \(\int_{V} \rho V dV\). Using the latter, the energy density is found to be \(0.5 E^2 \varepsilon_0\), as is well known. If you integrate the latter only over free charge and ignore bound charge, you write \(\epsilon \nabla \cdot E= \rho\), use integration by parts, and obtain the first result. Does the first result neglect the energy from bound charge? If not, why does \(0.5 E^2 \varepsilon_0\) break down (I.e. why can’t one find the energy with a dielectric by treating the bound charge as its own independent ch…

I'm trying to understand Archimedes principle. I understand that the buoyancy force on a submersed object is equal to the amount of water displaced by the object. But how do you measure these things? How is it that a force can equal a displaced object? How do you measure the buoyancy force and then compare it to an amount of liquid that was displaced? Wouldn't these be two different types of measurements? How then can they equal each other?

Hello, Here's my problem: I have a firm steel rectangle. dimensions : Length: 530mm Height: 610mm Width: 15mm This one is filled with oil up to 550 mm high. The rest of the volume is occupied by air. All this under normal pressure and temperature conditions. Now I put this steel rectangle on a heating device that will heat the oil up to 85C. Taking into consideration the thermal expansion of the oil, its volume will increase by 'x' m3 due to the increase in temperature (the thermal expansion of the steel will be neglected). My question is this: The new volume of oil will affect the air pressure as it will be compressed. What…

I used to have a site I could go to and plug in various variables and figure things like mass, radius, gravity, density but that site has closed and I can't seem to find another that allows me to plug in data and get back real world figures. Does anyone know of a site where I can do that?

The science channel had a physicist who travels the world measuring to a hundredth of a gram the weight of a plaster gnome. He demonstrated that the gnome loses 2 hundredths of a gram from the ground floor to the 108th floor of a high rise. His error was in claiming that the closer you get to the center of the earth, the heavier your weight will be. Quite impossible, no? So I created a crude representation of how weight changes with below grade elevation, but can't quite manage to determine the depth at which measured weight is maximized. A very neat problem in my opinion.

Whenever volume of water is measured, its lower layer is noted. While in the case of any colored liquid, upper layer is noted. Is it so? Why?

what is Newton 1 2 3 law ?

Can the voltage adjuster in the imagine i uploaded be able to adjust the current to an electro magnets to make the strength increase and decrease to the strengths I would want them to reach?

Hi, just a question on electromagnets. If you had 2 electromagnets repelling against each other with a 140kg pull weight, would there be a way you Can adjust the distance between one of the magnets with a dial that could reduce and increase the pull weight ? E.g the further away the magnet the less pull weight it would have e.g 70kg and then turning the dial it to a higher setting it would pull the magnet closer pull the weight to 110kg?

Hey there, I need a bit of help with a project I am working on. Two parts here that help answer the same question. First, when fusing H into He, is there a specific energy needed for fusion to occur or can fusion occur at any energy level or velocity. Part two: When creating heavier elements in the lab, they blast a less massive particle at a more massive particle in the hopes that they will fuse to make the desired element. Is there a specific velocity that the lighter particle is accelerated to? Thanks! Isaac

if you take an ordinary quartz crystal and apply a voltage to it, will it vibrate? if not, how do you make it oscillate? and will it be enough that you can feel it?