Work Definition and 998 Threads

So I understand in a battery that an anode (such as zinc) and a cathode (such as carbon) are separated by an electrolyte. I also understand that the electrons want to flow into the cathode, but can't get to them, so as soon as a conductor connects the two terminals, current can flow. However...

Homework Statement Homework EquationsThe Attempt at a Solution The work done is maximum in the path (3) as the area covered by this path is maximum. Now, dU = dQ + dW, the work done is minimum in the Path (1) , so dQ should be maximum. Hence, the correct options are A and C. Is this correct?

Homework Statement 1. Do research to find out what artificial gravity is and how it is related to centripetal motion. Explain how artificial gravity could be created in a weightless environment and give a reason why we would want to do this.Homework Equations None. The Attempt at a Solution...

Homework Statement I am doing a little bit of research about op amps. What i know so far from the book it that op amp have a very large open loop gain. To reduce the gain to desired amount we need resistor which connect output to invering terminal(negative feedback). Homework...

So, I'm a little confused on how batteries work. I understand they convert chemical energy into electrical energy. I also understand that the battery consists of an anode and a cathode with an electolyte in the middle to force the electrons from the chemical reaction to have to follow the wires...

Homework Statement This is a conceptual question. An ideal gas is compressed to half its initial volume by means of several possible processes. Which of the following processes results in the most work done on the gas? a) isothermal b) adiabatic c) isobaric d) The work done is independent of...

Can someone please share complex problems interrelated between Kinamatics, Force, Linear Momentum, Work and Energy along with final answers to cross-check.

When using the work-energy theorem (Wnet=ΔE), when do you take gravitational potential energy into account? Change in energy implies all types of energy involved, but in what cases would PEg be a part of it?

Hi! I've found some excercices and expanation of Work always consider a constant velocity, this is a net Force equal to cero. Like spring or gravity excercices related against a force applied. Does this relation with constant velocity has some usefull explanation why? Should I always assume...

So again, I’ve got this analytical question on my mind and it’s been bugging me for a couple weeks now. So my question is, how do sound waves work? I’m talking about if you put two radios facing each other playing different songs. What would happen? Is it if waves match then they just combine...

For the polar equation 1/[√(sinθcosθ)] I found the slope of the graph by using the chain rule and found that dy/dx=−tan(θ) and the concavity d2y/dx2=2(tanθ)^3/2 This is a pretty messy derivative so I checked it with wolfram alpha and both functions are correct (but feel free to check in case...

From time to time we have some minor threads mentioning real vs complex representations of fermions, chiral theories, etc and how a loophole is to use mirror generations, but I do not remember some detailed discussion of how does it work. For starters, do we need an even number of...

I use an Olll filter to view emission nebula such as the Great Nebula in Orion. What is the mechanism by which Olll in such nebula emit photons of the wavelength that passes through my filter?

Hi everyone. I've been doing a lot of reading regarding electric potential and electric potential energy. Unfortunately, I have a lot of confusion regarding this topic, as I keep receiving different information. My main confusion is regarding the signs, positive or negative, of work and it's...

I always thought that the principle of virtual work (PVW) is valid for all structures, including continuous structures (like bars, beams, plates, etc.). However, in his book 'Fundamentals of Structural Mechanics', Hjelmstad states that the PVW is only valid for discrete systems with N particles...

Homework Statement A man weighing 180 lbf pushes a block weighing 100 lbf alone a horizontal plane. The dynamic coefficient of friction between the block and plane is 0.2. Assuming that the block is moving at a constant speed, calculate the work required to move the block a distance of 100 ft...

I work now as a technician on a military base. Looking to get my Bachelors in ME. The problem is I have zero experience in engineering ( as expected ). No internships, nothing. I guess my question is will I have to start from the bottom of the pay scale when I graduate? By the time I am...

Homework Statement How much work does gravity do when a 3 kg brick falls 15 m? Homework Equations W=Fx? The Attempt at a Solution I transferred the mass of the brick to weight (gravitational force) and got 29.4. I used this number for the force and the 15 for distance, or x. Does 441 J make...

Homework Statement Homework Equations internal change = $$\frac{3}{2}n.R.(T2 - T1)$$ Work = P.ΔV The Attempt at a Solution 1) T2 = $$\frac {P2. V2 . T1 }{P1 . V1} = 1.2 * 10^3$$ 2) Q = Internal change = $$\frac{3}{2}n.R.(T2 - T1) $$ $$ = \frac{3}{2} * 1 *8.3*10^{-3}*(12*10^2 - 3*10^2) $$...

Homework Statement Homework Equations The Attempt at a Solution I do not understand why is mgh2 is being subtracted from the overall equation instead of added. I am able to construct each of the work components but when building the overall equation I'm having a problem of understanding...

Hello, #1 As my teacher explained "T=F•r•sin<" all clear so far. When i attempted to apply the formula it crossed my mind that the unit of T is (N•m), if so how do we solve for distence 0< r < 1. #2 Another question if the unit is {(kg•m)/(s^2)}•m why did he represent moment with Newtons...

With ground where it is, how does current travel the rest of the circuit? I thought that as soon as current met ground it was gone

Homework Statement I'm trying to figure out the setup of an experiment I have to complete. The experiment calls for a rubber band to be secured by rods on the sides, and for a clothespin to be attached to the rubber band. I have to figure out how far back the clothespin needs to be pulled down...

Homework Statement There are three problems: 1. How much power is required to lift a 10.00 kg barbell at a speed of 3.0 m/s? 2.What is the average power supplied by a 70.0 kg firefighter climbing up a ladder in 10.0 s? 3. A man pulls a wagon with a force directed 22.0˚ above the horizontal...

Hi, This is my first post so apologies if I'm not clear enough or if I am posting in the wrong place. I am doing my 3rd year project at university and I am creating diffraction gratings. My supervisor shown me a Canadian note and if you shine a laser through the maple leaf it will shine on the...

Homework Statement A student pushes a 0.65kg box Ali g a desk. When he stops pushing the book, it moves 85cm before stoping (slowing down in this period). Coefficient of friction between book and Table is 0.27.Calculate the work done on the book by the friction. Should it be positive or...

Homework Statement Homework EquationsThe Attempt at a SolutionTaking the engine to be a Carnot engine, ## \eta = \frac { T_h – T_c } {T_h} = \frac { W} {Q_h} ## ...(1) ## Q_h = C(T_h – T_f) ...(2) \\ Q_c = C(T_f – T_c) ...(3) \\ W = Q_h – Q_c = C(T_h + T_c – 2 T_f) ## ...(4)Solving...

Hello, I have assembled the following AM radio reciever circuit: Purpose of the circuit: To receive AM radio signals and provide the output audio of these signals ( demodulated ). Circuit elements: L ~ 1.5mH , C ~ 300pF , Amplifier IC: LM324N , Diode: 1N4004 ...

I have a system of equations, and one of them is this : ##\int(1-U(y))Dy - H*\int(U(y)-U(y)^2)dy=0## Can Newtons method work if I approximate this integral to be ##\sum_y(1-U(y))-H\sum(U(y)-U(y)^2)=0## y is a set integers in range ##[1,1000]## I have Newtons method working for this same system...

Homework Statement A 20.0 kg block on a horizontal surface is attached to a horizontal spring of k = 2.0 kN/m. The block is pulled to the right so that the spring is extended 10.0 cm beyond its unstretched length, and the block is then released from rest. The frictional force between the...

I have a question about work. If Newtons 3rd law of motion states there is an equal and opposite reaction for any force. Now if for example I apply 500 Newtons of force on my dresser and move it 5 meters I used 2500 joules of energy. Now because the dresser is equally putting that much force...

I am struggling to fully grasp the concept of flow work for a non-deformabable control volume. Nearly every source puts it in this way: flow work is the work required to push fluid into and out of the control volume and as such is defined as Pv on a unit mass basis. But how can this work be...

Every year since the 90's I come back to some of my pet topics in physics, like statistical physics. This time it was the reading of a Wikipedia article on entropy that surprised me. The derivation of the second law from the Gibbs entropy was unknown to me. I didn't know how heat, how change of...

Since positive charge on the photocatode increases work function of electrons, does charging metal photocatode negatively decrease work function? If not, why?

Please check the image below. My algebra is bit rusty. Please explain the second step where the common factor is taken out.

My chemistry course says that work done by the system is negative, but physics course says that work done by the system is positive, I'm sure I'm missing something and I really need to understand it. Thanks.

Homework Statement A man pushes an 80-N crate a distance of 5.0 m upward along a frictionless slope that makes an angle of 30° with the horizontal. His force is parallel to the slope. If the speed of the crate decreases at a rate of 1.5 m/s2 , then the work done by the man is: (a) –200 J (b) 61...

Greg Bernhardt submitted a new PF Insights post Work Ethic Is a Key to Success for Science Majors Continue reading the Original PF Insights Post.

Homework Statement Homework EquationsThe Attempt at a Solution I first said it's B, since force throws up = positive. gravity down= also positive, please help asap thanks

Homework Statement I don't have an answer key to these questions and it's my first time dealing with problems like this. so was wondering if my process is correct! Homework Equations q = m*deltaT*C q = mols*Hvap The Attempt at a Solution So, my reasoning behind this work is that there was heat...

I am having a problem with visualizing why Newton's Law of Universal Gravitation (NUGR) holds true when objects get close together. F=Gmm/r^2 makes sense for planets that are far away because each object can be treated as a point with gravity acting at the center of each object. For a person...

A charge of +2.5 micro coulomb is at the origin and a +3.5 micro coulomb is at the point (3,0). What is the velocity of a proton when it is at (6,0) if it was released at (5,0). My solution: $$E_0=E_f$$ $$PE=KE$$ $$Since...Work = -PE$$ I can calculate the work it takes to move the proton from...

Homework Statement Find relation between real normalisation constants ##B_1## and ##B_2## for the following wavefunction, $$ \Psi_k =\sum_{k=1,2} \frac{B_k}{\sqrt{4\sigma ^2 + 2it}} \exp (ip_k (x - \frac{p_k}{2}t) - \frac{(x - p_k t)^2}{4\sigma ^2 + 2it}) $$ The working is rather long so...

From Newton's 2nd law F = ma and a = F/m(acceleration and mass are inversely related when force is constant) But in w = F.d , F =w/d(but d and F are not inversly related just as above) I think there's something wrong in my question, please point it to me or please answer it.

Homework Statement An object of mass 100kg is acted on by a constant force as it moves through a displacement at a constant speed of 7.2m/s. What is the net work done on the object? Homework Equations Wnet = ΔK Fnet = 0 The Attempt at a Solution I know that the answer is zero because the...

Homework Statement For a positively-charged particle at the origin, and a negatively-charged particle lying to its right on the positive x-axis, the electrostatic force on the negative charge is attractive, and Coulomb's Law gives the magnitude of that force: F = k |Q1| |Q2| / x^2 k is...

What is ΔEp = ΔEk + W I have come across this formula, but i haven't seen it before. What is it used for?

How do you workout average acceleration without time? I have Initial velocity ,final velocity & distance. With this I have to workout... 1) Average acceleration 2) Time take to accelerate from initial to final velocity Regards Someone a little confused

If Alice and Bob had a large number of particles entangled together (with state of either 0 or 1), could Alice send information by breaking the entanglement of particles with state of 1 (by flipping the state for example) so that Bob measures 50% of particles to be in the state opposite of 0...

In the question below i know 200/480 V is rated voltage at primary and secondary side of a transformer, but '13' is what i do not know. Also how does the solution work out? i have tried every possible thing. Thanks(Sorry if i could not phrase my question in accordance to the pattern)