Equilibrium Definition and 1000 Threads

Homework Statement Two uniform 150 N rafters rest on frictionless floor, held together by a rope. A 500 N load is held at their apex. Find tension in the tie rope. Homework Equations ##torque= rFsin \theta =Force*Moment Arm ## The Attempt at a Solution The angle ##\theta## in the picture...

Hello, Let us imagine a solid immersed in a liquid in a container such that the density of the liquid is less than the density of the solid. This means that the solid must sink. Let us study the solid when it reaches the bottom surface and is now at rest. The forces acting on the solid when it...

Homework Statement A 50 lb weight is attached to the end of a spring. The spring is stretched 6 inches. Find the displacement from equilibrium of the weight after (π/8) seconds, if the weight is released from a point 2 inches above the equilibrium position. Round to the nearest length of a...

Homework Statement Good afternoon, I hope someone could help me with this problem, it is killing my head. I have an aerogenerator, I already find the torque excerted by the air (75.8N) and the force transmitted by the gear (1010.6N). The problem comes when I try to draw the free body diagram to...

I am currently working on designing a linear brake/lock for a completely different purpose but it will be based on the same principle as in a quick clamp shown below. Before building a prototype I do want to make some rough calculations to check dimensions, angles etc. etc. However, I am for...

Consider chain of two radioactive decays ##A \to B\to C##. The equation that regulates ##N_B## is $${\frac {\mathrm {d} N_{B}}{\mathrm {d} t}}=-\lambda _{B}N_{B}+\lambda _{A}N_{A}$$ I can't understand why the activity of ##B## is get as ##\lambda_B N_B##, for example at page 20 here...

Homework Statement Consider the reaction : A⇔2B (⇔ stands for reversible). 1 mol of A and 2 mol of B are taken in a closed container at equilibrium. Suppose the pressure is increased, how much of B (by moles) will decompose to restore equilibrium ? Homework EquationsThe Attempt at a Solution...

Homework Statement An electric field is created by an uniform linear charge with a linear charge density is 40 nC/m. Find the potential difference between the two points, one of which is situated 5 cm from the line charge and the second at 10cm. Two charges, q and -3q, are situated at a...

Is it possible for an open system to reach thermal equilibrium? why/why not?

Homework Statement I had a question on a test and I got the wrong answer, but I still don't understand why. It was a Le Chatelier problem about the equilibrium shift, and it described the decomposition of CaCO3 CaCO3(s) <->CaO(s) + CO2(g) The question asked something along the lines of "If...

Homework Statement >For a solution that contains 0.10 M HCN and 0.10 M NaCN, which statement is false? A) This is an example of the common ion effect. B) The [H+] is larger than it would be if only the HCN was in solution. C) the [H+] is equal to $K_a$ D) Addition of more NaCN will shift...

Homework Statement A thin stiff uniform rectangular plate with width L (L =AB) is lying on two inclined surface as shown in Fig. 3-1. The angle between the horizontal surface and the left inclined surface is α, and that between the horizontal surface and the right inclined surface is β. It is...

Homework Statement The problem is question 2(a) in the attached pdf. I seem to find myself at a dead end and am not sure where to go from here - I will attach my working in a separate file, but basically I need to show that the oscillator passes/crosses over the x = 0 boundary at a positive...

Homework Statement A circular hoop of radius R rotates with angular frequency ω about a vertical axis coincident with its diameter. A bead of mass m slides frictionlessly under gravity on the hoop. Let θ be the bead’s angular position relative to the vertical (so that θ = 0 corresponds to the...

Homework Statement Homework EquationsThe Attempt at a Solution I've resolved all the relevant forces (tension, weight, normal force), but upon looking at the mark scheme, there is no normal force to be resolved. Forgive me if I'm missing out on something obvious, but shouldn't there be a...

Homework Statement The questions are in the comment box. Sorry! https://www.img.in.th/image/V9K8Rg Homework EquationsThe Attempt at a Solution 1. I think α = 90 because BD is normal force. and I don't know anymore PS. sorry for bad english

Homework Statement Between two parallel walls we tighten a rope. One end of a rope is tied a little higher on the wall than the end on the opposite wall. On the rope we put a pulley with mass m which slides to equilibrium position. Homework EquationsThe Attempt at a Solution I assumed that in...

Good evening. I'm currently studing dense matter and nuclear matter above 10^8 g/cm^3, and i know well how to insert a beta equilibirum condition in a free Fermi gás at T=0. \sqrt{K^2_{F,n}+m^2_n}=\sqrt{K^2_{F,p}+m^2_p}+\sqrt{K^2_{F,e}+m^2_e} But how do i insert the same condition of...

Homework Statement Homework Equations Energy band diagram equations. The Attempt at a Solution This is more of a conceptual question, but this is the problem I am working on for reference. What is the difference between a flat band diagram and an equilibrium diagram? I know what they will...

Homework Statement I don`t know if the image will show so I`m also adding a link to the image of the problem. This problem is a modification my professor made to the one in the link below(*), he changed the rigid diathermic partition into a movable partition. I`m supposed to find the...

Suppose a pond contains $x(t)$ fish at time $t$, and $x(t)$ changes according to the DE: \[\frac{\mathrm{d} x}{\mathrm{d} t} = x\left ( 1-\frac{x}{x_0} \right )-R_f\] where $x_0$ is the equilibrium amount with no fishing and $R_f > 0$ is the constant rate of removal due to fishing. Assume $x(0)...

Homework Statement I am trying to understand which forces are up or down and left and right. I am trying to also find out the torque that would be clockwise and counterclockwise on the figure. Homework EquationsThe Attempt at a Solution Original Picture Edited Picture Arrows indicate...

Homework Statement Homework EquationsThe Attempt at a Solution rxF I'm trying to find the moment of the 50lb about the x,y,z axes. So, i did the vector from the origin to the top of the larger wheel crossproduct with the force vector of 50. Thus, Vector Origin to Wheel x F vector = (0.2i...

Homework Statement The wheelbarrow and its contents have a mass of m = 63 kg with a center of mass at G. Determine the normal reaction on the tire and the vertical force on each hand to hold it at θ = 30∘. Take a = 0.27 m , b = 0.43 m , c = 0.78 m and d = 0.10 m . (Figure 1) Homework...

Homework Statement See attached photo Homework Equations Stress = F/A Area = pi d^3 / 4 Sum F h = 0, Sum F v = 0, Sum M = 0 The Attempt at a Solution Hey everyone, after reading the question a number of times and not knowing for certain where to start, I figured because the stress and area...

Homework Statement A cube balanced with one edge in contact with a table top and with its center of gravity directly above the edge is in _______ equilibrium with respect to rotation about the edge and in _________ equilibrium with respect to rotation about a horizontal axis that is...

Homework Statement This is a practice olympiad problem A light rod with length l is hinged in such a way that the hinge folds in one plane only. The hinge is spun with angular speed ω around a vertical axis. A small ball is fixed to the other end of the rod. (a) Find the angular speeds for...

Hello Physics Forums, I am studying the equations related to analytical ultracentrifugation. The equation I am interested in describes centrifugation equilibrium, ie at the point in time when sedimentation is balanced with diffusion in the ultracentrifuge. Fortunately, unlike the Lamm equation...

https://www.physicsforums.com/attachments/220647 Homework Statement Two uniform planks each of mass 10Kg and length 2m, are arranged as shown in the picture. Find the maximum value of x for which the top plank will remain in equlibrium. Homework Equations F= (mgl)/hThe Attempt at a Solution I...

Hello Everybody! My name is TanX and I got a figure in my mind while studting concepts related to Vertical Circular Motion. I tried finding a solution to it (i.e) I tried finding the condition for movement of the particle in the figure that had come in my mind... Homework Statement So here is...

Homework Statement N2 + 3H2 --> 2NH3 (all gases) Why is such a high pressure needed? Calculate the equilibrium constant at 500k then estimate the percentage conversion at equilibrium at 1 bar total pressure, assuming the stoichiometric ratio of N2:H2 is 1:3. Repeat the process at 50 bar...

Homework Statement Homework EquationsThe Attempt at a Solution Honestly , I have not been able to understand the question . I am totally clueless about the part written in parenthesis . All I understand is that since the length of the rod is not negligible ,value of gravity at the location...

Hello all. Been a long time since I took a thermal course. I'm looking for a formula to work with the thermal stabilization of something. Specifically, I want to minimize the time required for thermal stabilization to occur and how to mathematically calculate what that set temperatures should...

Homework Statement An object is suspended on a frictionless slope inclined plane by a rope parallel to the incline. If the angle of the incline is 25° and the tension on the rope is 5000 N, what is the weight of the object Homework Equations ∑F=0 The Attempt at a Solution So in my eyes, you...

Homework Statement An artist must push with a minimum of 75N at an angle of 45° to a picture to hold it in equilibrium. The coefficient of friction between the wall and the picture frame is 0.30. What is the mass of the picture? Homework Equations ΣF=0 Ffr=μFN F=ma The Attempt at a Solution I...

Homework Statement There is a lever rod of length 3.43 m, weight 44 N and uniform density. The lever rod is pivoted on one end and is supported by a cable attached at a point 0.902 m from the other end. The lever rod is in equilibrium at angle of 68◦ from the vertical wall. The cable makes...

Hello! I was wondering if anyone could give me a hand with the following problem. I am stuck and I don't know how to solve it. You can see attached the problem and my work so far. Thank you very much for your help.

1. The problem statement, all variabHello. I uploaded a picture with the problem that concerns me. As you can see from my work so far...I have tried to solve the problem but I'm stuck. I have tried a few times and I'm starting to question myself if the problem is correct or not. Please give me a...

Greg Bernhardt submitted a new PF Insights post Statistical Mechanics Part I: Equilibrium Systems Continue reading the Original PF Insights Post.

Homework Statement Two masses, A and B, are placed on the edges of a mass of 20 kg which is homogeneously distributed figure such that an unstable equilibrium is achieved. If the mass of A is 12 kg and the mass of B 16 kg, how large is the distance x from the left end of the board to the...

Hi everyone. Our mechanics professor warned us that in the mid-term exam some students reached the right answer on some questions but their method was wrong. For this reason sometimes I'm worried when I reach the correct answer but the way I did it is different from the solution guide. And I...

Hi everyone, Our professor gave us a bunch of solved problems to practice with before the exam, and this one I'm struggling with: I'm trying to work through the solution step by step, and I get stuck at the point (3). What I understand is that we want to get the value of RH, which is...

Hi everyone, This is not really a homework question per se since it's not an assignment. Basically, our physics professor gave us a 100+ page syllabus filled with example questions and solutions and I am practicing with them by doing them one after the other. This one question I'm having...

Homework Statement A closed, thermally-insulated box contains one mole of an ideal monatomic gas G in thermodynamic equilibrium with blackbody radiation B. The total internal energy of the system is ##U=U_{G}+U_{B}##, where ##U_{G}## and ##U_{B} (\propto T^4)## are the energies of the ideal gas...

The uniform boom shown below weighs 668 N, and the object hanging from its right end weighs 386 N. The boom is supported by a light cable and by a hinge at the wall. Calculate the tension in the cable and the force by the hinge on the boom (both in N). (Enter the magnitudes.) Tension in the...

https://arxiv.org/pdf/hep-th/0405270.pdf I was reading this paper where ideas presently originally by Dyson, Kleban, and Susskind about de Sitter equilibrium have been expounded by the authors. I have a few specific questions. 1. Could de Sitter space exist, for instance, in the heat death of...

Homework Statement Find the concentrations of all ions in the solution at equilibrium after 0.213 L of 0.433 M aqueous Cu(NO3)2 solution is mixed with 0.213 L of 0.120 M KOH solution. Ksp for Cu(OH)2 is 1.1E-15. Homework Equations n=m/M [Cu][OH]^2 = Ksp .. ?The Attempt at a Solution ok so for...

Homework Statement Consider a rigid 2.60-m-long beam (see figure) that is supported by a fixed 1.30-m-high post through its center and pivots on a frictionless bearing at its center atop the vertical 1.30-m-high post. One end of the beam is connected to the floor by a spring that has a force...

Homework Statement 173 g of water at 20°C is contained in a copper container of mass 327 g. An additional 129 g of water at 100°C is added. What is the final equilibrium temperature (in degrees C) if we treat the system's water and container as isolated? Homework Equations Q = mcΔT The...

Hi everybody, Given a generic reaction ## Reagents ↔ Products ## the velocity of the reaction is ##R = R_{right} - R_{left} ## To take in account that the velocity of the reaction will slow if approaching the equilibrium we say that $$ R = R_{right}(1 - \frac K K_{eq}) $$ Although it seems...