System Definition and 1000 Threads

The figure is in the attached image. My attempt: I(wheel-disk system) = 0.5mr^2 + MR ^2 = 0.5(0.2kg)(0.1m)^2 + (1.5kg)(0.3m)^2 = 0.136(kg)(m^2) Fnet(of object) = Ma Mg - T = Ma T = Mg - Ma Fnet (wheel-disk system) = (M+m)a Mg- Ma - Fr = (M+m)a a = 0 because system in equilibrium Mg -...

Having spent five months as an undergraduate with physics major, I found that there are two types of students who come to study physics: 1. For a job, and 2. For pursuing research. This thread is concerned with the second type only. Among many other problems, here are two that have concerned me...

Homework Statement:: Finding the distance between the back surface of the first lens and the front surface of the back lens. Homework Equations:: 1/f = 1/s_o + 1/s_i I have two positive thin lenses that are separated by a distance of 5 cm. The focal lengths of the lenses are F_1 = 10 cm and...

Hiya Hiya. I'm trying to build a solar system simulator for research purposes, and this does not seem to be all that easy. As in, my firsts tests have the moon shooting out of the solar system... I was wondering if you folks could offer some guidance. So, since it's for research, accuracy is...

i have been stuck on this question from my assignment, i have tried solving it in many ways, but apparently i am either bad at this or i just don't understand the question haha. * As a prudent engineer, the main shaft is now subjected to loading condition when only brake is applied. Show with...

For a system of interacting particles, is it possible to define single-particle phase spaces? If not, why?

(This question is on the elementary side...) In the Schrödinger picture, the state is dependent on time. If you have a state composed of several particles, generally you can break them up, with each one depending on local time. But in an entangled system, say of two particles, you can no longer...

Hi everyone, I am currently trying to work something out in regards to non-equilibrium thermodynamics. If I have a block of metal in vacuum that is being heated by a laser with a constant power P, is it even possible to be able to describe the emission of radiation by the block via the Stefan...

I understand the derivation of T= 2π√m/k is a= -kx/m, in a mass spring system horizonatally on a smooth plane, as this equated to the general equation of acceleration of simple harmonic motion , a= - 4π^2 (1/T^2) x but surely when in a vertical system , taking downwards as -ve, ma = kx - mg...

My Solution: For the displacement graph, the gradient is crucial to predict the behaviour of the displacement of the block through time. At 1: System is released - velocity is zero, considering forces acting on block, kx < mg, as block is observed to move downwards, and object is...

The theory is that that the trapped air in pipe A would create enough pressure to raise the water 600 mm in pipe C, Design and parts: 32 mm x 1 metre pipe (A) running from the stern floor (open end) forward with the front end raised 100 mm, then turned 360 deg and reduced to 10 mm (pipe B)...

Is there a well-known system that can collect small quantities of water from air, like maybe 6 oz/day? Should take up at most a cubic foot

I am trying to understand attracting, Liapunov stable, asymptotically stable for given coupled system. I don't have any Liapunov function. Just two coupled systems such as ##\dot{x} = y##, ##\dot{y} = -4x## or sometimes normal systems ##\dot{x} = -x##, ##\dot{y} = -5y## How can I approach...

Suppose a bullet with high speed strike a wooden block and move together after collision. We know there is loss in total KE of bullet-wooden block system. The question is, if the part of the loss in KE of the bullet is transfer to heat energy, HOW to prove the CONSERVATION of ENERGY in this...

So I figured out the equation, but it is probably wrong because the answer doesn't tally. Since the string is inextensible, I can assume that tension is the same for both sides, and acceleration for both masses is the same too So: I can say that the acceleration of 2kg block =acceleration of 7kg...

Hello all, I am working on a lab report for physics, and am a bit stuck on one aspect. The basic layout of the pulley system is attached. (This is a diagram I made, so if there are any inaccuracies in this one either, I am happy to fix it. So, I mostly understand the lab. My TA said, though...

hi all, firstly i need to calculate point location in new coordinate system. ı have 2 line segments and a point(x,y,z) in word cartesian coordinates system. For example, my first line segment is (0,0,5) , (50,0,3) locations and second line segment is (0,6,3),(0,-6,7) locations in cartesian...

Are there rigorous texts that treat the topic of raising real numbers to rational powers without treating it a special case of using complex numbers? I'm not trying to avoid the complex numbers for my own personal use! My goal is to determine whether students who have not studied complex...

Hi, I'm working on a project for a thermal fluids design class in which a theoretical Thorium reactor is to be designed and modeled, and I'm a little bit at a loss for how to start analyzing the problem. I know the system will have 4 fluid systems: an enriched FLiBe system connected via HX to...

What are the specific objections to Felix Finster's Casual Fermion System besides "many objections" and "very exotic, and very, very far from mainstream"? The comment in the summary above says forget about the Dirac sea. I am sorry, but CFS is an extension of the Dirac sea idea written in...

When measuring pressure drop across a compressed air system shown in the included figure, I get different results depending on the system downstream of the actual component I am measuring pressure drop across. Btw this is a real experiment that has been ran. The numbers below are different but a...

1) the motion equations for ##m_2## are: $$T-m_2 g=0 \rightarrow T=m_2 g$$ ##m_1##: $$T=m_1\frac{v^2}{r_0} \rightarrow \vec {v_0}=\sqrt{\frac{r_0 g m_2}{m_1}}\hat{\theta}$$ 2) This is where I am stuck, first I wrote ##m_2## motion equation just like before, but in polar coordinates...

Hi! So this is my first homework ever of Hamiltonian dynamics and I am struggling with the understanding of the most basic concepts. My lecturer is following Saletan's and Deriglazov's and from what I have read and from my lectures, this is what I think I know. Please let me know if this is...

can anyone explain me how O negative and COO negative acts as electron releasing group,I understood how alkyl groups acts as electron releasing group but I can't understand this

I am attempting to calculate the force (in KgF) of a water pump + nozzle system. I have the pump curve (head vs. flow rate) for the pump, the diameter of the connection hose (2 inches) and the nozzle diameter (1 inch). The connection hose between the pump and nozzle is very short (approx 10 cm)...

I'm a bit lost at how to exactly start this exercise... As far as I understand we need to first determine ##d\tau_E## and ##d\tau_S##. First question: Since we can neglect the Earth's movement, can I also neglect the movement of the satellite with respect to the far away observer? If so, I...

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This question showed up on my grade 12 physics test. The problem I have with this question is that I did not know the direction that the system would accelerate in, so I just solved as though the mass on the inclined plane would accelerate the system. I expected that if it would accelerate the...

Hi! I'm a student of pharmaceutical sciences which means that my physics knowledge isn’t that great ahah, if I say a big mistake in the following text, a thousand "sorrys" ahah: So, I am now writing my master thesis and currently I am finishing writing a part where fluid mechanics are...

The solution is an application of the law of conservation of energy. Start with equation (1). The masses are in equilibrium and are not accelerating. This implies that ΔK = 0, because the kinetic energy will not change without acceleration. Thus, we are left to find equation (2) in terms of θ...

Magnitude of acceleration of system: a = (4.59kg - 1.71kg)(9.81N/kg)/(4.59kg + 1.71kg) = 4.48 m/s^2 Velocity of lighter mass when heavier one hits the ground: vf^2 = vi^2 + 2ad = 0 + 2(4.48m/s^2)(2.60m) vf = 4.83 m/s [up] I am not sure what to do from here? I don't really understand what...

S(t)= Hi all! Μy attempt to solve it: I'm stuck here. An opinion ? Thanks.

Hello, Some trouble came up today with designing a 50 ohm system for a wireless powering project. I'd like to increase the frequency range for which my system impedance is 50 ohms in order to reduce power losses due to mismatch. I've simulated two RLC circuits in OrCAD SPICE to demonstrate my...

I don’t even know where to start. I especially don’t know how I would find the energy inside of the pump that would then be released to shoot a T-shirt.

It was recently announced that J0740+6620 contains what is probably the most massive neutron star found to date: https://arxiv.org/pdf/1904.06759.pdf This paper concludes the companion to the MSP is a helium-atmosphere white dwarf: https://arxiv.org/pdf/1902.11150.pdf Based on a crude...

Hi ! I'm trying to understand why does we say that RLC circuit is a dynamic system. An example of a dynamic system that i know is a pendulum. The swinging of a pendulum depends on the applied force but also on the past force. What about the output of RLC circuit ? What is the relation between...

I am building a planet that will orbit a sun and I need help My world has 11 planes/asteroids. the planet Le Bear has multiple life forms on it. It takes 378 days to rotate around the sun. My planet has a circumference of 8199.49 miles. there are 12 months of 28 days and then 1 1/2 months of...

Hi PF: The house my wife and I purchased recently is our first one with a basement and it already has a radon mitigation system installed. Unfinished basement. I've sent my short-term test to the lab and I have a long-term test that I intend to start this week. Do any PF members have any...

So the normal diffusion equation looks like \frac{\partial c}{\partial t} = k\frac{\partial}{\partial x}\left(\frac{\partial c}{\partial x}\right) I know how to get explicit and implicit solutions to this equation using finite differences. However, I am trying to do the same for an equation of...

Well, first I tried to understand the relation between the velocities and accelerations of both bodies and I got that the velocity of ##B## is half the velocity of ##A##. This is because a change in length of the cord "that touches ##A##" must be equal to the change in length of the two cords...

What is meant by the nodes of a decentralised manufacturing system? Are these the points where the manufacturing is carried out?

I have known and used this theorem for a long time solving problems ("Calculate the CM of the some given shape"). I took the theorem to be "obvious" and didn't know it could be proved (and that indeed it was a theorem at all). I can make no attempt at the proof. Any help would be welcome.

This problem was asked in one of the most prestigious exams in India: JEE Advanced, unfortunately it was considered to be ambiguous for the scope of given examination and hence no official answer is issued for it as such.(BONUS marks to all) And so many solutions were posted on Internet which...

[Mentor's note - this post has been edited to ask the interesting physics question while not falling afoul of the forum rule prohibiting discussions of perpetual motion] On the left is pure water (blue), and on the right is concentrated salt water (green). The red walls in the middle are...

Good morning, I have a system that consists of a huge number of boxes, it is not important to know how many, each containing a binary number: In every cell, the probability that there is a '1' is p, so the probability that there is a '0' is equal to (1-p). What I do is take them in groups of N...

Hello, I am curious if I have this correct and if it has a name. A thin walled cylinder is spinning on its axis along its length in a closed system. It begins to draw itself in converting its invariant mass to kinetic energy. In polar coordinates ##E=\gamma_\theta m c^2, L=\gamma_\theta m...

Homework Statement: A binary star system consists of M1 and M2 separated by a distance D. M1 and M2 are revolving with an angular velocity w in circular orbits about their common center of mass. Mass is continuously being transferred from one star to the other. This transfer of mass causes...

I want to start off here saying I took the problem has finding a potential function, and not a general solution, so I worked to only find one function that works. I already confirmed that this function can be written as a curl of a vector function and the gradient of a scalar function. Since...

The plane autonomous system $$x' = -ax + xy\\y' = 1 - by - x^2$$ has a unique critical point when ##ab>1## Since if we set x' = 0, then either x=0 or y=a If y=a, then for y' = 0: ##1 - ab - x^2= 0## , but if ##ab>1## this leads to ##x^2<0## which has no solutions and thus ##y\ne a## The only...