System Definition and 1000 Threads

I tried using coordinates system from cone, but not got what actually want to get. Any idea from you will greatly appreciated. Thanks

Was just wondering if there is anything fundamentally preventing a system of planets being in permanent orbit around a black hole, without ever spiralling in. Assuming that the black hole doesn't absorb any significant amount of additional mass. Of course I know it wouldn't provide any energy to...

Ok.. When me and my husband were dating, I lived in a state 800 miles away from him. I noticed he got sick more often than I did.. I thought it was poor immune system and genetics, because I barely ever got sick but he and his family did. When we got married and I moved to where he was.. I...

The question is solved in a single step by taking the blocks as a system and using conservation of linear momentum in the horizontal direction as there is no net force acting in the horizontal direction. Conserving the momentum we get, m x v + M x 0 = (m+M)v', so,,v' = mv/(m +M).where v' is the...

Hello! If we have a 2 level system (I will call the states g and e for ground and excited), and a laser field (which can have any detuning relative to the spacing between g and e), it can be shown that that the total number of particles is conserved under the laser-atom interaction hamiltonian...

Hello everyone, I would need help to model a motorized system controlled in a closed loop. It is a personal project. At first, I am looking to obtain the transfer function and simulate the system on computer. In a second step (not the aim of this thread), I would like to use this simulation to...

I am trying to solve the given question based on energy conservation,but am stuck with the analysis of the equations. The question says find the velocity of the bigger block when the smaller block initially given a velocity v and sliding on the horizontal part of the bigger block reaches the...

Hello there, can I get some help with (b) please? first of all I wanted to ask.. can is it permitted to use different systems in one exercises? like f.e. for conservation of energy to find the velocity of ##m_3## I used as system only ##m_3## but for the collision I used the 3 masses as the...

Is my answer correct? And if not, why?

The point (1, 5) is on the curve: y=ax^2+bx+c. This point gives the linear equation: 5 = a + b + c. A second point on the curve, (2, 10) gives the linear equation 10=4a+2b+c. A student called Erika thinks that the point (2, 19) is also on the curve. 5 = a + b + c. 10=4a+2b+c 19=4a+2b+c the...

Consider the following system of congruences: ## 2x\equiv 3\pmod {5} ## ## 4x\equiv 2\pmod {6} ## ## 3x\equiv 2\pmod {7} ##. Then \begin{align*} &2x\equiv 3\pmod {5}\implies 6x\equiv 9\pmod {5}\implies x\equiv 4\pmod {5}\\ &4x\equiv 2\pmod {6}\implies 2x\equiv 1\pmod {3}\\ &3x\equiv 2\pmod...

Summary: Can these two equations be solved for x like a system of linear inequalities, and how? ##x- 2y \le 54## ##x + y \ge 93## We start with ##x- 2y \le 54## ##x + y \ge 93## Multiplying the second equation by 2, we have ##2x + 2y \ge 184##. We cannot seem to cancel the y out with the...

Consider the following system of congruences: ## 5x+3y\equiv 1\pmod {7} ## ## 3x+2y\equiv 4\pmod {7} ##. Then \begin{align*} &5x+3y\equiv 1\pmod {7}\implies 15x+9y\equiv 3\pmod {7}\\ &3x+2y\equiv 4\pmod {7}\implies 15x+10y\equiv 20\pmod {7}.\\ \end{align*} Observe that ## [15x+10y\equiv 20\pmod...

Consider the system of congruences: ## 3x+4y\equiv 5\pmod {13} ## ## 2x+5y\equiv 7\pmod {13} ##. Then \begin{align*} &3x+4y\equiv 5\pmod {13}\implies 6x+8y\equiv 10\pmod {13}\\ &2x+5y\equiv 7\pmod {13}\implies 6x+15y\equiv 21\pmod {13}.\\ \end{align*} Observe that ## [6x+15y\equiv 21\pmod...

[Mentor Note -- postprocessed attached image for clarity] Hello! Looking for a formula(s) on how I can determine the Torque and RPM needed on the chain (by hydraulic motor) to move the load in the illustration at 240 inches per minute. The load will vary, so I won’t ever really need to push...

I'm having some kind of mental block. If I extend ##l_x## by ##\delta## ,I expect the hanging mass to move ##\frac{ \delta}{2}##. I can't figure out how this is the case from the constraint: $$ l_x+l_1=C $$ ##C## is an arbitrary length I keep getting that ##l_1## changes by ##\delta##, but...

I have a difficulty when making the energy-conservation-equation for the second step. When making the equation, we need to know the exact position (measured from the sun) of the rocket after it is freed from the Earth gravitation. But, where exactly does the rocket free from Earth...

Hello, At my work I came up with the following question: Say we have a vacuum chamber. Inside the vacuum chamber we have at the bottom a water bath. The rest of the chamber is filled with a air and water vapor mixture. The whole system is placed in a room, is at room temperature and is in...

There is no friction mentioned by the question so I assume the plane is frictionless but can the sphere roll without slipping if there is no friction? This is my attempt: Equation of translation motion of object A (assuming A moves upwards): TA - WA sin θ = mA . aCOM (A) TA = mA . aCOM (A) + WA...

just hypothetical question, First off I am not very knowledgeable in pumps. Let's say you have a pump to pump fluid, i don't think the type matters, self priming as I understand it creates a vacuum with the air in the system to pull the fluid towards the gear pumps. I'm wondering what happens...

Find the problem below with the solution indicated; The text approach is much clear to me... My way of tackling the problem is as follows; using echelon form (row reduction method) \begin{bmatrix} 1 & 1 & 2 & -5 &3\\ 2 & 5 & -1 & -9&-3 \\ 2 & 1 & -1 & 3&-11\\ 1& -3 & 2 & 7&-5...

I have been given the task of modeling the heat transfer from a light source of known power into a system consisting of two connected materials. I must find the temperature change in the bottom surface. The two materials are initially in thermal equilibrium with the surroundings. My first...

this is an easy problem but would it be possible to consider car-car system. What I did on paper was carsystem and because they have the same properties(mass en speed) multiply by ##2## solution for car-car-earth system I assume is the following if it is possible? solution for car-car: law or...

Hey'all. First of all, I'm not fluent in English, so forgive me for the spelling mistakes. So, I'm trying to make a simulation of a solar system using python 3.9. It's not complicated, but my teacher wants me to do it using the Basic Verlet method, and that's what is bugging me. He told me do do...

If two sets of objects, of similar size but different mass, were to be part of a rotating celestial system, how differently would they be distributed? Would the distribution of the lower-mass objects be more spread out, while the higher-mass objects would be concentrated toward the centre?

So in this picture friction is also assumed, but if we assume friction as an energy don't we need to consider the system to be earth, roller-coaster car, roller-coaster itself(due to friction force)? I actually still had this question from a previous coverage of this material lol... I just...

While reading this thread on Stack Exchange... https://physics.stackexchange.com/questions/113092/why-does-a-system-try-to-minimize-potential-energy ... a question came to mind : - Say an object is launched away from Earth at a velocity greater than the escape velocity. This system will not end...

(a) By setting up a coordinate system with the x-axis pointing to the right and the y-axis pointing downward we have ##\begin{cases}-kx_{eq}+T_1+F_{s}=0\\ -RF_{s}+rT_1=0\\ r_p (T_2-T_1)=0\\ -T_2+mg=0\end{cases}\Rightarrow x_{eq}=\frac{mg}{k}\left(1+\frac{r}{R}\right)## which coincides with the...

Hi PF! A circular cylinder contains an inviscid liquid, which is softly disturbed (i.e. velocities are small). There are no body forces, which implies the equilibrium free surface is that of a spherical cap with radius ##R## (see figure A). Inviscid implies we can assume potential flow, such...

I am trying to come to terms with the two concepts of gravity, direct attraction between bodies (say dust even) and attribution to the curvature of space (time) Looking at a physical sea coast I can envisage how every instance of the mass gravitational interactions of individual atoms or smaller...

We know that if we take two particles and assume no external force is applied then by Newtons third law total momentum gets conserved after collision. If we take three particles and there is collision between them and no external force then the momentum is again conserved for each pair like in...

How did you find PF?: Google I have an off grid home that uses a spring fed gravity flow water system. The spring is about 200 feet up a steep mountain- and very low flow. The pipe run starts at 2” pvc and eventually is 1.5” pvc. Once down the hill the water flows about 1 mile down an old...

An article came up on Phys.org about a white dwarf drawing in material from the planetary system surrounding it. Is this the ultimate fate of our solar system? https://phys.org/news/2022-06-dead-star-cannibalism-planetary-far-reaching.html...

answer:

I think the the time given doesn't matter since no torque is acting on the system, but not sure. Therefore, all we need is to determine the angular momentum about the axis passing through O and perpendicular to the plane of disk. This will involve finding the moment of inertia of smaller disk...

Hello! I have the following initial value problem: \[ x' = x + 2y + 3z \] \[ y' = 4y + 5z \] \[ z' = 6z \] All I'm looking to do is find the general solution to this system, and as long as I'm doing this correctly I have these answers: \[ y(t) = K_2e^{4t} + \tfrac{5K_1}{2}e^{6t} \] \[...

Hello. I am having some difficulties regarding this problem. I am not sure, actually, how to relate the angle rotated by the cylinder ##\phi## and the angle drawed by the bead itself ##\theta##. I have been thinking in two alternatives: a) The first one is that, since there are no friction...

I'm stuck in a problem of a spring mass system with a pendulum attached to it as showed in the figure below: My goal is to find the movement equation for the mass, using Lagrangian dynamics. If the spring moves, the wire will move the same amount. Therefore, we can write the x and y position...

Start velocity is 100 km/h, at 1.5g for 0.5 seconds the end velocity will be 73,52 km/h. So the energy can be calculated if the mass is present, but it is not given. Is there a way to calculate the regenerated energy with the given information?

I determined the partition function of the particle A, B and C. C should be the same as B. I then considered the situation, where all particles are in the system at the same time, and drew a diagram of all possible arrangements: The grey boxes are the different partitions, given that we...

I will summarize briefly my reasoning for both letters, since the answer is immediately after that: A) The work is quasi-static, and the pressure is approximatelly constant and equal to the atmospheric pressure, so the works is $$W = -p\int dV = -p_{0} (V_{0}-V)$$ B) The work is fast, fast...

Pathria, Statistical mechanics, pg 93 "We consider the given system ##A## as immersed in a large reservoir ##A'##, with which it can exchange both energy and particles. After some time has elapsed, the system and the reservoir are supposed to attain a state of mutual equilibrium. Then...

How Apple, Google, and Microsoft will kill passwords and phishing in one stroke (Ars Technica) The key acronym is FIDO (Fast IDentity Online). As I understand it, basically, you authenticate yourself to a website or service on your phone using a fingerprint or facial recognition as can already...

Problem: A system contains two identical spinless particles. The one particle states are spanned by an orthonormal system ##|\phi_k>##. Suppose that particle states are ##|\phi_i>## and ##|\phi_j>## (##i \neq j##). (a) Find the probability of finding the particle in the state ##|\xi>## and...

I'm pretty confused by this but I have a few thoughts. Since the sun takes up most of the mass of the solar system, I was thinking maybe I'm really looking for the escape velocity of the sun? So I would use the mass of the sun for M and the radius of the sun for r. My other thought was to add up...

Hello guys, I’m studying Newton’s Mechanics at the first year of engineering, and I would like to ask one question about torque. In my book I found this statement ‘’ Given a system of particles, it’s always possible to determine a pair of forces which torque is indipedent from the pole chosen...

Whicle has 4 wheels, inside is oval closed room with fan that blow inside air to the wing. Wing produce difference in static pressure in direction of travel. Will vehicle move forward or not? If I look just at pressure difference at wing, vehicle will move forward but I know from Newton 3 law...

Based on the formulas, variable ##m , k, L,g## do not change so my answer is (a) but it is not correct. Why? Thanks

It seems the practice is to enter the table with evaporator air intake wetbulb temp and condenser ambient temp. I'm trying to understand the theory that translates these readings into the proper target superheat. Thanks

Dear all, the following problem is not a home-work problem. I have come up with this question for myself. Nevertheless, I am stuck and need your help. The question is: Can I calculate the distance between points A and B from this information? And if yes, how? I think it should be possible...