Equilibirium Definition and 65 Threads

So please find both screenshots below taken from these youtube videos: Why in the first problem, the tension in the string, from which a mass hangs, is not included when the teacher is placing all torques in the equation (see image)? Why in the second problem, the normal force from the rod...

I would like to understand the topic discussed in this thread more. https://www.physicsforums.com/threads/tipping-over-a-table-how-much-overhang.1012197/post-6598527 As I understand it, I can find the load required to tip the table can be calculated by this formula. L<W a/x This is illustrated...

we assume that we have an exergonic reaction , a substrate going to a product , is the negative ΔG′° the principal reason that the equilibrium favors the product (there is more product than substrate at equilibrium )?, or it is not and that depends on other factors? , thanks .

$$ \begin{array}{c} \mathrm{HA}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{A}^{-}+\mathrm{H}_{3} \mathrm{O}^{+} \\ \mathrm{K}=\dfrac{\left[\mathrm{A}^{-}\right]\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]}{\left.[\mathrm{HA}] \mathrm{H}_{2} \mathrm{O}\right]} \quad...

So basically, I got close to a zero for my solution to this problem. I'm guessing based on the posted solutions that I wasn't able to get partial credit due to the fact that my coordinate axis was aligned with the slender bar and not in its usual perpendicular position. This resulted in...

I am struggling to understand Callen's explanation for stability, I understand that the concavity of S(U) must be negative because otherwise we can show that this means that the temperature increases as the internal energy decreases (dT/dU<0) but I cannot understand equation (8.1) which...

The following are my works for the problems: I put squares on my final answers! Thank you!

It is desired to remove the molecular hydrogen present in a flask. What will be better to introduce, ##Cl_2## or ##Br_2##? Why? ##2 HCl <-> H_2 + Cl_2## (1) ##k = 3,2.10^{-14}## ##H_2 + Br_2 <->2 HBr## (2) ##k = 2.10^9## I thought about turning equation (1) to make the...

According to the book "Principles of Statistical Mechanics" by Amnon Katz, page 123, ##\alpha## must be such that ##\exp ( -\alpha N ) ## can be expanded in powers of ##\alpha## with only the first order term kept. Is this the necessary and sufficient condition for small deviations from...

So I have this problem The soultion to the problem gives me this drawing But I don't understand what ##F_h## and ##F_v## is

i am having a problem in understanding the question , what will be the volume of hcl ? and how is the reaction going to take place ? please help me i am stuck on this problem for quite a long time.

I've written out the half reaction 8e- + 9H+ + SO42- = HS- + 4H2O and I know the logK = 4.25 (that's the constant mentioned in the prompt) I've written out the equilibrium statement of 10^4.25 = ([x^1/8]*[H2O^1/2])/([10x^1/8]*[e-]*[(10^-8.2)^9/8] However, from there, it seems like I have two...

For finding the pH of the acid, I made use of the equilibrium law (or the law of mass action) to arrive at the degree of dissociation which I later used to get the [H+] concentration. I am stuck in finding the pH of the salt solution. ##CH2ClOO^- + H2O <---> CHClOOH + OH^-## Could you please...

I was thinking that we can equate the electrostatic potential energy and the spring energy (as the force is similar to that of a spring so energy will also be 1/2kx^2 ) but i am not getting the correct ans but by equating the net force on one charge to kr i am getting the correct ans can...

I isolated the member ABC and drew the free body diagram: α is then calculated using inverse tan: Tan-1=(6.25+15)/50=23.03 Then force of member BD on the joint can be found by sum of all moments around point A. Then Ax is calculated which is equal to BD×Cos(α)=235.2×Cos(23.03) Ax=216.48...

Homework Statement Homework Equations Formula of Kp and Kc The Attempt at a Solution You will easily be able to identify that the reaction will proceed in the forward direction when some inert gas is introduced. So,my question is that why won't the amount of chlorine formed increase in...

Homework Statement A car is lifted vertically by a jack placed at the car's rear end 40cm off the central axis, so that the weight of the car is supported by the jack and the two front wheels. The distance between the front wheels is 1.60m, the distance from the axis connecting the two wheels...

Homework Statement For silicon at T=300K with donor density ND=2×109cm−3, acceptor density NA=0 and ni=8.2×109cm−3, calculate the equilibrium electron and hole concentration Homework Equations n_0=\frac{N_D-N_A}{2}+\sqrt{\frac{N_D-N_A}{2}^2+n_i^2} p_o=\frac{n_i^2}{n_0} The Attempt at a...

Homework Statement I had to answer which of the pulley arrangements illustrated (see picture) is in equilibrium (the drawing went a bit difficult, please see all outer boxes as equal in size and the middle ones as well) I managed to answer that it is arrangement C, by finding out that...

Homework Statement See this question. Homework Equations Pressure=Height*Density*Gravity The Attempt at a Solution I think P_atm=P_gas. I think so because for the two liquids(oil and Hg) to be in equilibrium the net force on them should be zero. And,since they are not getting displaced...

Hello, Let us imagine a rod resting on a frictionless horizontal surface such that the rod is made up of 2 identical molecules. Let these molecules be named A and B from left to right. If we pull A to the left and B to the right with forces of equal magnitude, the rod must remain at equilibrium...

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 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 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 if a beam fixed at two points is on an angle say 45 degrees from the x or y-axis instead of running parallel to x-axis in most questions does this effect calculations? The force acting upon it would be a load directly downwardsHomework Equations N/A The Attempt at a Solution...

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...

I was reading the *Statistical Physics An Introductory Course* by Daniel J.Amit and need some help to understand a certain passage: In an isolated composite system of two paramagnetic system: System a with ##N_a## spins and a magnetic field ##H_a ## System b with ##N_b## spins and a...

Homework Statement Problem image: https://prnt.sc/gvhjso In this case I have to find the reaction forces at the point E (the Fx, Fy, and the Moment at point E) by using the given data. The 20kN forces at the load AC are concentrated, and are 1.8m far from each other. The tension of the cable is...

Hey So I am still a beginner in Physics and work asked me today to calculate if a 63mm Bore Pneumatic Ram will do the required job. Anyway, so I know how to calculate the weight capacity the ram can handle if it is at a 90 deg angle however if the ram is on an angle then I am stuck. I need to...

Homework Statement I'm trying to solve for this problem below.How would you be able to get the force in member ID and GC? Find the reaction forces in member AFGH Homework Equations ∑M = 0 ∑[F][/y] = 0 ∑[F][/x] = 0[/B] The Attempt at a Solution I dismembered all of its parts but no matter...

Homework Statement The board shown below is being held in equilibrium in the vertical plane by three smooth rods at A, B, and C Determine the magnitudes of forces at A, B, and C in terms of the weight of the body, W. Homework Equations Moment = f*r Here's a diagram The Attempt at a...

Homework Statement A 1.0kg of ice at 0◦C, 3.0kg of water at 0◦C, and 5.0kg of iron at temperature T are placed in a sealed and insulated container. cFe =400J/ kg◦C ,cWater=4200J/ kg◦C , cIce= 2000 J/ kg◦C latent heat for ice is 3.3×105 J . The equilibrium temperature is 20◦C.Homework...

Homework Statement A human holds a ball of mass 8kg at his hand, so that the forearm is perpendicular to the upperarm. The distance between the elbow and the center of mass of the forearm is 0.15 meters, the distance between the elbow and the muscle is 0.05 meters and the mass of the forearm...

Homework Statement Homework Equations [/B] ΣFy = 0 ΣFx = 0 TanΘ = sinΘ/cosΘ...

Hello members, I wish to produce and "store" "Methane" gas. I wish to accomplish this task by conducting out a reaction between carbon-dioxide an water. I have my own source of energy and I completely understand that the reaction is endothermic. The reaction is: CO2 + 2H2O + energy = CH4 + 2O2...

Homework Statement A rigid wire frame is formed in a right triangle, and set in a vertical plane as shown. Two beads, of weight W1 = 1.5 N and W2 = 2.5 N, slide without friction on the wires, and are connected by a cord. When the system is in static equilibrium, what is the tension in the...

Homework Statement I feel so stuck. Given the Logistic Equation: $$\frac{dP}{dt}=kP(1-\frac{P}{A})$$ a.). Find the equilibrium solutions by setting $$\frac{dP}{dt}=0$$ and solving for P. b.). The equation is separable. Separate it and write the separated form of the equation. c.). Use partial...

I understand that the change in Gibbs Free Energy at equillibrium is 0 and this leads to the equation -deltaH=TdeltaS. My questions here is that if a reaction is at equillibrium, how can there be any change in enthalpy or entropy at all? Why wouldn't these terms be 0?

What is the pH of a solution made from 34.6 ml if 3.45*10^-4 M of H2SO4 added to 41.7 ml of 4.56*10^-4 M of Al(OH)3? I know how to find H+ and OH- and pH I also know how to use x mol / L, but I cannot get them to click together. Everyone keeps telling me to use RICE but my professor never...

Homework Statement U = Ax2 - Bx3 Homework Equations du/dx = 2Ax - 3Bx2 The Attempt at a Solution If I was given a potential energy function U = Ax2 - Bx3 and am asked to find: 1) The expression for the force as a function of x. 2) The equilibrium points and determine if are they stable or...

A ball of mass 15.47kg rests on a table of height 0.73m. The tabletop is rectangular with a mass of 12.11kg, supported by 4 thin legs. The width of it is 134.0cm and length of 63.7cm. If the ball touches the tabletop at point (67.0cm, 16.4cm) relative to corner 1, what is the force the tabletop...

Homework Statement Find the displacement from the equilibrium position of the particle that is in the distance x=£/12 from the wave source, for the moment t=T/4. The amplitude of the wave is A=0.2 m Homework Equations x=A*cos(wt)=A*cos2*pi/T* t The Attempt at a Solution x=£/12...

Homework Statement see attachment ***indicates correct answer Homework Equations F=ks The Attempt at a Solution I do not understand how this works, and I haven't been able to find any examples of this.

When does the value of the "Equilibrium Constant (K)" equal one ? and what does that mean ?

Homework Statement This is a more than one part question that depends on answers from the previous parts, which I have so I will not rewrite those questions. I will write the question I am facing difficulty with: Answers from previous parts: Length = 1.95 m (From top of chains to center, its...

Homework Statement A mass M hangs in equilibrium on a spring. M is made to oscillate about the equilibrium position by pulling it down 10 cm and releasing it. The time for M to travel back to the equilibrium position for the first time is 0.5s. Which line, A to D, is correct for these...

Homework Statement If m=5.0kg, φ=30◦ and μs =0.87, what is the minimum force needed to make the box slide down the slope? [/B] Homework Equations force of status friction is less than or equal to the normal force multiplied by the coefficient of static friction F,normal=mgcosφ The image...