System Definition and 1000 Threads

The slinky is designed to fully contract in 1 second. During this one second, the mass is weightless and move up at constant speed of 1m/s. After 1 second the mass gain 1m height in potential energy. Am I missing something?

In a closed system consisting of a set of particles not at rest relative to each other and acting on each other only by classical mechanical collision (i.e. billiard balls model, not including gravity or other long-range interactions), does conservation of momentum imply that the system will...

Can everyone help me solve this mystery? Starship has 8 sets of RCS thrusters, 4 at the top and 4 at the bottom near the base. The 4 at the top some youtube videos show them above the top fins: Nitrogen RCS test: But some other videos show them below the fins: Are they...

Given the CTFT X(ω): and here are my solution to find CT signal x(t) associated with the given CTFT , but i got stuck at the limit part

This was the question (The line below is probably some translation of upper line in different language) For disc it was ma^2/2 For ring it was ma^2 For square lamina it was 2ma^2/3 For rods It was different Please explain Thank You🙏

Hello guys, here's another problem I'm having troubles with(I have attached my working out not for laziness, but clarity since steps are many). I started by defining a polar coordinate system, and then drawing the FBD and KD to get to the equations of motion for particle P. I identified 3...

Goldstein 3 ed, pg 171, under" rate of change of a vector " : The author derives the relationship between the change of a vector in a stationary and rotating coordinate system. In the process he uses this assumption :>It is no loss of generality to take the space and body axes as...

I have to find the center manifold of the following system \begin{align} \dot{x}_1&=x_2 \\ \dot{x}_2&=-\frac{1}{2}x_1^2 \end{align} which has a critical point at ##x_0=\begin{bmatrix}0 & 0\end{bmatrix}##. Its linearization at that point is \begin{align} D\mathbf {f}(\mathbf {x_0}) =...

[Mentors' note: This thread was split off from https://www.physicsforums.com/threads/system-potential-energy-and-nonconservative-forces.1009237/] This is not a particularly helpful way to think about things; For a general mechanical system, you usually split the specified forces into external...

Hello, I am trying to get my head around the idea of nonconservative forces doing work and changing the potential energy of a system. First of all, forces acting on a system can be: a) internal and conservative b) internal and nonconservative (friction, pushes, pulls, thrust, etc.) c) external...

the image on the right shows the problem. the blue ink is the equation someone else gave me, and I don't understand why the force between box2 and ground goes down... (the red is me) the force f is applied to box2 so that it pushes box2 down, so isn't the spring k2 supposed to push upward?

... by a factor of 10, then would it operate exactly the same way as if it did not contract? I ask this because there could be an observer at a sufficient speed for which our solar system contracts by a factor of 10. Wouldn't our solar system and its contents have to behave differently for the...

If we change the orientation of a coordinate system as shown above, (the standard eluer angles , ##x_1y_1z_1## the initial configuration and ##x_by _b z_b## the final one), then the formula for the coordinates of a vector in the new system is given by ##x'=Ax## where...

Suppose I have an object consisting of a hemisphere of radius r and a cone of radius r and height h. The shapes are glued to each other on their faces and the object is set standing on its hemisphere side. Depending on the value of h, the center of gravity for the system will change. I have...

hi guys i am encountered with a question that is : two protons in a helium atom stand close together,approximately at a distance of 2 fm. what is the potential energy of this system ? i can understand the concepts that are potential of a particle or potentail of a object etc but can't...

Just want to clarify some concepts. There seems to be difference between reference frame and coordinate system. See https://en.wikipedia.org/wiki/Frame_of_reference#Definition . A reference frame is something has physical meaning and is related to physical laws, whereas coordinate system...

I am given this system of differential equations; $$ x_1'=2t^2x_1+3t^2x_2+t^5 $$ $$ x_2' =-2t^2x_1-3t^2x_2 +t^2 $$ Now the first question states the following; Find a fundamental matrix of the corresponding homogeneous system and explain exactly how you arrive at independent solutions And the...

Our system of interest has a duct on the left and a piston chamber on the right that make the shape of the letter T rotated 90º clockwise. The smaller tube on the left is abbreviated as P1 has an unspecified length while the piston chamber is P2. The air in P2 heats up and expands while the...

I've no political agenda. This is strictly a math question about optimization. Those addressing it should do so strictly from a mathematical perspective. Thank you! If the world simply had one global currency, like Bitcoin, and everyone had an account, then the sum total of all accounts...

I assume that as the light years to another Star reduce the position of the Star will change relative to other references in the navigation calculations. So what adjustments would be necessary to a Starship's course as it gobbles up the distance to maintain pointing it's nose at the destination...

I am looking for the right size of battery/pure sine-wave inverter to power a system for a few hour when there is a power outage. The system of TV/DVD/Internet uses less than 200 watts at about 1.6Amps. I could just buy a commercial system which runs about 1000$ or assemble a similar design for...

For example having looked a solution sheet, I know that ##x(t)=\sin(t)## is not a solution for any system of the form ##\dot{x}(t)=f(x)##. I assume this is rather simple, but I simply cannot get my head around why it wouldn't be. I'm guessing it has to do with the dependence on ##x## rather then...

So far I have: The velocity of the belt will be the same for pully A and D, so we can calculate the angular velocity of pulley D: ## V_A = V_B ## ## \omega_A r_A = \omega_D r_D ## ## ((20*3)+40)(0.075) = \omega_D (0.025) ## ## \omega_D = 300 Rad/s ## My next step was to determine the angular...

The Nyquist curve for a fifth order system with transfer function G(s) is given in the attached photo. Here we have plotted G(iω) for both positive and negative frequencies ω. The transfer function G(s) has no poles or zeros strictly on the right side of the imaginary axis Point −1 is marked...

Homework Statement:: [...] Molecules with an extended π system such as linear polyenes and polyaromatic compounds are well described by resonance hybrids as well as by delocalized orbitals in molecular orbital theory. Relevant Equations:: N/A This is not a Homework question. I was reading...

How can I mathematically model a real system and predict values from that system? I have a real device that produces data that I can graph. The data looks like a sinewave. I want to use an sinewave fit equation to predict some of the measurements because of how long it takes to run a...

I am doing a learning project by writing a simulation that includes capacitance and current flow amongst capacitors that may potentially be in parallel. I don't care about certain details yet - dissipation factor, frequency dependent effects, temperature. Tiny capacitences within diode junctions...

We are working on new software for one of our measurement systems (written in Python). The new system is capable of measuring more devices simultaneously than before so keeping track of what we are doing is important; it will also be more automated. One of the things we want to implement is...

Hi, I was watching the following video. So, a low Earth orbit continuously transmits data to a geosynchronous satellite via a laser link. The geosynchronous satellite relays the data to a ground station on Earth via a radio link. In case of European Data Relay System (EDRS) laser communication...

I start this thread about a comet that probably (hopefully) will be of common interest in the coming months (or years). And, no, Earth orbit will not be affected. https://arxiv.org/pdf/2109.09852.pdf

Hey! 😊 I am looking at the following but I haven't really understood the exercise statement. Could you explain that to me? :unsure:When the memory of a computer system is addressed by bytes, the storage of an information unit larger than one byte can be done in one of the following ways: a)...

Alright, so I have a question. Now, on planets such as our Earth, there are a longitude and latitude as well as altitude. If I am not mistaken, I believe the latitude and altitude are part of what affects gravity, or weight, on a planet. Latitude makes it so that the object in question is...

Hi guys, I don't really know how to cope with this problem, maybe just because I can't properly understand the data. In the figure we have a beam with its loading(plus a force of 15kN), a pivot O and support at the rightmost point. I would say that in order to find the equivalent system, I...

In the other thread of a similar name it was stated, and probably rightly so, that I wasn't using rigorous terminology or that I wasn't using them in a rigorous way. While I was making certain assumptions about the ability to interpret the 'jargon' I was using, it seemed to be a serious...

Could the existence of the 9th planet of the solar system is possible under these arguments of existence of it some where in the out scurt of solar system? The evidence for Planet 9 comes from its gravitational pull on other bodies. If the planet exists, its gravity will affect the orbits of...

Continuing the discussion in the 'Assumptions of Bell's Theorem' thread, I'm hoping to explore the question of the location/position of the QM system prior to measurement. I may have some bias or underlying assumption that is affecting the conclusion that I am drawing and, by exploring this...

I'm curious about the ads I've been seeing on TV about these Energy Storage Systems. Anyone have any knowledge about them? image from https://sunwatts.com/20-2-kwh-generac-pwrcell-energy-storage-system/ Thanks in advance

A person wrote that ##L=\frac{1}{2} m (\dot{r}^2+r^2 \dot{\phi}^2 +\dot{z}^2)## But, how to find equation of that coordinate system?

I want to make a collimator lens which can convert the diverging rays from and LCD at finite distance screen into parallel rays. But in order to reduce the aberrations, using system of lens is preferable than using a single lens. Can you suggest the way to create this kind of system please. I...

> The set up: At left end, the rope is pulled down with a distance $dx_1$ by a force of constant magnitude $F$, the mass of $M$ is wrapping around by rope on the right and moves up by a distance $dx_2$ due to this. Problem: Find relate the two displacements. I thought of applying energy...

Currently, I have a mv fan ducted system with two fans in parallel, one duty and standby (each with 7000cmh). If I were to run both fans at the same time, do I get 14000cmh in total?

Which is a higher entropy state: solar system as it is today with planets going around the sun at fixed distances in an orderly fashion OR all the planets and sun bumping into one another and forming a single body? If the entropy of the combined single body is higher, why doesn't the solar...

I was cleaning out my email archive after being notified I was out of storage. I decided to keep these. Enjoy. (original at: https://dingo.care2.com/cards/flash/5409/galaxy.swf) This one would be impossible on a phone and slow on a laptop, use a fullsize computer if available. I couldn't...

I am trying to differentiate between states in a quantum system of graphene with open boundaries in one direction and periodic boundaries in the other direction. The eigenstates have been simulated with the eigenenergies, but how would I proceed in calculating the expectation value of the...

First I calculated the forces that were working against mass B. m(A)g sin 30 + μm(A)g cos 30 = 12.86 N The force working with mass B is m(B)g = 9.8m(B) I thought I could solve for B using F=ma where 12.86 N = (2kg+m(B))*(0.58), but of course, 12.86 N is just the force required to make the...

I'm no expert but, as I understand it, in an open system, one that can take in energy and matter from outside of itself, the overall entropy level can be prevented from increasing (and can actually decrease) under the right conditions. I have three questions: 1. Can the kinds of quantum...

Ok so for a compound microscope system like the one below, Magnification power is ## MP = M_T * M_A ##. My present understanding is that ##M_T## refers to the magnification by height ratios of the object through L1, and ##M_A##, in this case, refers to the ratio of unaided and aided angles of...