Work Definition and 998 Threads

The equation I know for adiabatic work is W = P1V1((V1/V2)ϒ-1 - 1))/ϒ-1, but this involves ϒ, but I can use ϒ = Cp/Cv = Cv+R/Cv = 1 + Cv/R, does this seem correct? But I still have a P1

a) ##\rho = \frac{I}{c} = \frac{F}{A}## for a perfect absorber ##F = ma## where ##a = \frac{c}{t}## ##\frac{I}{c} = \frac{mc}{tA}## ##I = \frac{I^2 tA}{mc^2} = \frac{P}{A}## ##P = \frac{I^2 tA^2}{mc^2} = \frac{W}{t}## ##W = \frac{I^2 t^2A^2}{mc^2}## I am unsure what A is. I think it should be...

Hello, I have a little difficulty understanding how sublimation works, from what I have understood so far, the sublimation of ice for example occurs below its triple point (at a certain pressure and temperature but not atmospheric pressure but at a certain partial pressure). Does this mean that...

The heat conduction equation for a semi-infinite slab with a boundary condition of the first kind is as follows: The problem is delta is a very small number, so the first exponential will tend to infinity. I am programming this in Fortran and it can accommodate values up to magnitude of 310...

Hi guys I am doing a graphic design project and I would need to know how this tests to check if your drink is been spiked works. Whats the chemical that react to the most common drugs used? thank you so much!

Hi PF! I'm going through a backtracking tutorial here. That code runs well for me, and is below: %% LOAD DATA % Read a table of daily adjusted close prices for 2006 DJIA stocks. T = readtable('dowPortfolio.xlsx'); % For readability, use only 15 of the 30 DJI component stocks. assetSymbols =...

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...

I'm quite aware that according to Einstein light is a particle and a wave at the same time. However, I try to imagine how exactly would light expand. A photon must likely have a certain timing for expansion. I mean, after a photon is originated it immedialy multiplies itself into many other...

A recent preprint ( https://arxiv.org/abs/2112.15157 ) seems to imply that the focussing properties of an optical system can depend on the bandwidth of the sensor, and even on that of the associated electronics! It is argued there that if the ‘frame rate’ of the sensor is very high, photons...

Please, i need help

Hi, This post is about a 4-piston, 4 stroke internal combustion engine(ICE).Here is an youtube animation for such an engine. I actually have 2 questions. Q1: We have seen in demos and videos that in a 4-piston (ICE) engine, the pistons P1 ,P4 (pair 1) and P2, P3 (pair 2) are in phase when...

Short satire piece: https://www.mcsweeneys.net/articles/signs-you-work-in-the-cool-lab

It's late/early...I'm procrastinating on a project... Thought I'd ask a "dumb" question to satisfy my curiosity. I know computers have hardware (physical machine) and software (from the operating system to other programs/apps that can be downloaded onto the hardware to perform certain...

(I do understand there are many ways to formulate the FE method, but I wish to understand this one.) I understand that Hamilton's Principle is just that: a principle ( a law the recapitulates the equations of motion) I also understand that the Principle of Virtual Work (PVW) is a reformulation...

hello, I am trying to use latex in a thread, but for some reason it does not work, eg. v^a is displayed as v^a I am using firefox browser version 99. many thanks for your help

This statement has always confused me. Now my confusion is coming home to roast while we cover EMF. If we consider work mathematically as ∫f.dl and require integral to be path independent then of course the B-field does no work. However, it seems like there is a deeper meaning to B-fields do...

As seen by the image below a centrifugal clutch has a pin/hinge in one end of each shoe arm and dependent on the angle of the shoe arm in the fully extended position that will create a wedging action to further increase the friction against the drum beyond the centrifugal force alone. Kind of...

Just wondering if anyone here finds these video/picture leaks about UAP's (Unidentified Aerial Phenomenon) interesting and inspiring enough to try and figure out how they work? Pretty big game changer of technology and would be fun to discuss. I'm hoping at least someone agrees.

torque = rF = I*aT/r F = 0.5*aT*m_p W = F (tension in rope)*d = 0.5*aT*m_p*d Don't know because of unknown d

The reason I'm posting this is because I'm confused about the reasoning behind the equation. For oppositely charged particles, wouldn't work done increase with distance? According to this equation you get a higher magnitude of work done the smaller the distance. How can that be? I got the answer...

Since dW = F dot product dr dW/dr = F So dW/dx = Fx and dW/dx = Fy? I am looking at conservative forces where dU/dx = Fx and dU/dy = Fy

The Helium Network describes itself as a Community network of hotspots and claims to be a source of revenue for members. The literature (example here) only seems to talk in vague terms of providing connectivity via hotspots. I can see my neighbour's box on his chimney but I can't find any...

What is the difference between thermodynamic and mechanical work? Should they show equal values in an experiment? If yes, what possible errors could cause if there is a difference in their values?

y = 10*(1 + cos(0.1*x)) --> dy/dx = -sin(0.1x) dW = F*dx + F*dy = 10*sin(0.1*x)dx + 10*sin(0.1*x)*-sin(0.1x) integrating we have -100*cos(0.1*x) -10*sin(0.1x)^2 from 0 to 10*pi = W = 43 J. The answer says 257 J. Where am I wrong here?

Hi Geniuses... I joined this group because I have a question I can't answer myself. This is about cars. We're all familiar with classic cars having a grill up front and a space right after it, and then usually a radiator to cool the water/coolant in the engine. The discussion we're having in a...

##W=mgh=100(\sin 37)2=-120J## Right answer! But the question is asking work done by the person. So again I wrote two eqns ##F_N\sin 53+F_D\sin 37-100=10.2a_y## ##F_N\cos 53-F_D\cos 37=-10.2a_x## I just need ##a_x## and ##a_y## to solve.

As we always say eat food and rest because tomorrow you have to go to work. When we throw a ball up, it gains a max PE at some height. More the height more energy it has which makes it do more work. Is this right to say?

Hi! Good night ;) I have made the simplification of my circuit from the truth table using maps of. Everything looks good, however the simulation does not work in many cases according to the truth table. I notice that my boolean equation taken from the maps looks very big, is there the error...

The force is -Mg and distance is L/3. So W=-MgL/3. Not right! Maybe it’s done using COM but there is no additional information is given.

I'm trying to prepare a slideshow presentation of some lab-work we've undertaken. It's to be around 15 minutes in length and comprise of a few different (but related) experiments. I would like to ask if anybody knows of one or a few "exemplary" experimental physics presentations (on YouTube...

W=-mgd=2*10*1.5=30J. I don’t think this is right.

Its Good to be Back! From Resnik, Fundamentals of physics: Consider a particle of mass m, moving along an x-axis and acted on by a net force F(x) that is directed along that axis. The work done on the particle by this force as the particle moves from position ##x_i## to position ##x_f## is given...

Summary:: don't understand how can we use a voltage that has been already dropped. I don't understand the voltage divider. So R1 and R2 are the same. I have 10 V in beginning, then 5V drop across R1 and then i have 5V drop across R2. But how can I use the 5V if they already dropped at R2? If...

The problem states to find the work per particle to assemble the following NaCl chain. I just want to post my work here to verify I have the correct answer. My work is attached in the image provided.

So for the work done by the kinetic friction, the displacement along the incline is ##s## as given. What I canNOT understand is why the displacement in the y-direction is used for the work done by gravity i.e. ##W = -mgh## where ##h## is the displacement in het y-direction. This instead of the...

Hello guys, I was wondering if someone could provide me some help on this problem. for (c), I know that it will be 0 as the amount of word done from A to B = the am of work done from B to C. But, What I receive as seen in the picture is 2.11N Which is not correct.. In the first try I used a...

The answer key is zero because the areas are above and below x-axis and have equal magnitude so canceling out each other. But I am confused about the solution Area 1 is above x-axis but I think the work done is negative since the sign of ##F## and ##x## is opposite. Work done on area 2 is...

The answer key says the work done should be +.043cal. I am getting a negative sign. I have posted my work in the attached image. My logic is that since this a reversible engine we can say the integral of dQ/T=0. Looking at the cycle, Qc isi being absorbed (Qc>0) and Qh is being rejected...

Hi guys :)! I have a little problem with my homework protoboard circuit: First, i try to connect the simplification (A+BC), the LED it doest not turn off and not response when i push the buttons. All the components its ok, all its works. If the simplification works, the complete expression...

Proof: Let N be the number of coins. From the hint, we get the following Diophantine equation: N=77x+27=78y for integers x and y. Applying the Euclidean Algorithm produces: 78=1(77)+1 77=77(1)+0...

Hello, I'm getting a little confused and would appreciate some clarification. If a weight lifter lifts a weight of 2500N a distance of 2m, the work done by the weight lifter's force on the weight is 5000J. The work done by the weight force due to gravity is -5000J. The weight lifter then...

Hello! I'm currently building a cloud chamber, my end goal is to make it powered by Peltier chips but that won't happen until I can make it work with dry ice. I've been able to achieve a supersaturated layer of isopropyl alcohol in the chamber, however, even with very radioactive uranite...

Here's my list of variables and things to account for: m=100kg Wnc=5000J Wfriction=-500J -Kinetic energy will be doubled (though I don't know how that plays into it exactly) -I don't think there's any PE because it's on level ground My idea of what the equation might be: Wnc +1/2mv^2initial =...

What is the need to introduce the concept of work and energy when the motion can be completely understood by the concept of force and acceleration and momentum and velocity and displacement, etc? Why do we need to understand the same thing once again in terms of Work and energy? Also the kinetic...

Hi, *Excuse the crude visualization and possibly imprecise description - I'm not a rocket scientist :) So, I have a friend that has come up with a "new" concept for a rocket propulsion design, and although I have a hunch that it might not work better than existing designs I cannot really...

##\Delta K=K_f-K_i=W_a+W_g##.(##W_a##, work done by applied force and ##W_g##, work done by gravity) In case of uniform motion with velocity u, kinetic energy is equal. Change is zero. ##W_a=-W_g## If one force transfers energy into the system then the other takes out of the system. Energy of...

1. From resnik, Halliday “Kinetic energy K is energy associated with the state of motion of an object. The faster the object moves , the greater is the kinetic energy” If I am right this means that greater the kinetic energy, greater is its speed. 2. Force transfers energy to the body due to...

I encountered a problem regarding the appropriate sign needed to be taken for the work done on a dipole when it rotates in a uniform electric field and would appreciate some help. The torque on a dipole can be defined as τ=PEsinθ The work done on a dipole to move it from an angle ##\theta_0##...

Suppose we have a cylinder with one wall guard by a demon. Inside is one gas molecule moving left and right for simplicity. Now we want to closer the wall (compress the gas) without doing work. The job of the demon is push the wall closer when the gas move left and lock the wall when the gas...