The product of the force on an object and the displacement the object undergoes along the direction of the force.

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2
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4answers
174 views

How to calculate the work of the electrostatic forces in a parallel-plate capacitor?

The expression of the energy stored in a parallel-plate capacitor is: $$U = \frac{e_0\cdot A \cdot V^2}{2d}$$ with $e_0$ the vacuum permittivity, $A$ the surface of the capacitor, $V$ the applied ...
6
votes
3answers
316 views

Is work done by a pseudo force?

If a body is viewed from the frame of another body which is itself accelerating, will work be done by the pseudo force acting on the first body in the frame of second body ( provided the first body ...
1
vote
3answers
291 views

Is net work and total work same?

According to my text book Total Work = Delta Kinetic Energy = KEf - KEi But then work is defined to be dot product of Force (vector) and Displacement (vector). Also to my knowledge work is ...
0
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3answers
66 views

Does the work done by a person equal the work done on the object in this situation?

If you applied a constant force over a floor that has friction on an object, would the work done by the person equal to the work done on the object? Assume that the floor is flat and that the object ...
0
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3answers
84 views

Work in the First Law of Thermodynamics

The First Law can be stated as $\Delta U=Q-W$, where $W$ is the work done by the system. My question is what kind of work $W$ includes. $W$ certainly includes $PV$ work, i.e. expansion and compression ...
0
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3answers
70 views

Dealing with negative work

Dumb question, I'm working with vector fields right now, and one question on here tells me to assume an object can take on three paths from a to b. (paths not listed here) for times in [0,1] Now ...
1
vote
2answers
48 views

Sliding along a circular hoop: work done by friction

Assume a point object of mass $m$ slides along a hoop of radius $R$, starting from a position which makes 90 degrees with the line of radius connecting the center and the ground. Let the ...
0
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2answers
78 views

How work theoretically is zero, when person did do work while covering a distance then returning it?

$W = Fd$, meaning if a body moved a distance, say $3 m$, and returns, its distance will be zero and work will be zero. I do understand it mathematically and graphically but can someone explain it to ...
0
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2answers
45 views

Does the effect change if a continuing and constant force acts upon a mass?

If a continuing and constant force $F$ acts upon a body with the mass $m$, does the power (work per unit time) increase over time? It would mean that the converted energy per time unit increases. Is ...
0
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2answers
250 views

Work and free body diagrams

I am a bit confused with how to find work when there is a free body diagram. I am trying to work out this problem, and in it a box is being pulled at a constant speed by a rope at a constant angle ...
0
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2answers
72 views

Does inducing charge on a grounded conductor do work?

Imagine a grounded conductor as an plane of infinite area. If I bring a charge to a close proximity to the plane, it induces some charge distribution on the conductor. The question is: is any work ...
-1
votes
2answers
95 views

Work done by Friction. Can it be positive or zero?

The work done by frictional force is negative as it opposes the relative motion? Please explain when will the work done by friction be (i) zero (ii) positive ?
-1
votes
2answers
753 views

Work done by a conservative force

Wikipedia: A conservative force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Equivalently, if a particle travels in a ...
1
vote
1answer
208 views

Potential energy of springs and gravity, and work of a force

I am currently really stuck on this problem and I am not sure how to actually solve it, I think I can reason it out logically but I do not know how to show it. Here it is and under I will show what I ...
0
votes
1answer
30 views

Calculation of Work

Typically I see problems laid out along these lines. If you are lifting a 100 kg weight 1 meter how much work do you do? Work = Force * Distance Work = (100 kg) (9.8 m/s^2) * 1 m = 980 J But it ...
0
votes
1answer
28 views

Work done when applying an electric field?

On these example questions from MIT in the solution to 4.1 they write the work done by applying the electric field to be: $$W=V_0 \int \vec E \cdot d \vec D$$ Where does this equation come from and ...
0
votes
1answer
59 views

Is there a special name for thermodynamic process during which no work is performed?

Let $W$ denote the work done on a system during a thermodynamic process. Is there a commonly-accepted, dedicated term for a process during which $W=0$?
0
votes
1answer
30 views

Can the energy/power required to mix two fluids together be calculated?

Given two fluids; say for example oxygen and nitrogen gases. By simply introducing, again for example 1 liter of each gas into a closed container, the process of diffusion alone will eventually cause ...
0
votes
1answer
259 views

Work done by battery and potential energy of a capacitor

I have a doubt about the work done by a battery and the potential energy of a capacitor? 1- Consider a circuit where the capacitors are connected to the terminals of a battery. Through calculations ...
0
votes
1answer
85 views

Work done by friction on a body?

I know that when a body slides over a surface, the work done by friction is not stored as potential energy in the body. It is dissipated in the form of heat. But why is it not stored as potential ...
0
votes
1answer
54 views

Change in work done by dipole

How would you explain the intuition behind the equation $dW = -\tau d\phi$ for an electric dipole?
-1
votes
1answer
70 views

Confusion about the definition of Work

I am trying to make sense of the meaning of the definition of work. The original definition of work was also known as "the weight lifted through a height." I was hoping that our mathematical ...
-1
votes
1answer
135 views

Thermodynamics and Internal Energy

I've been working on this problem for quite some time trying to figure out the most efficient way of answering it, So here goes the problem: There is a container, containing a monoatomic gas with ...
2
votes
0answers
95 views

The formula for calculating work transfer for a reversible adiabatic compression

Should we not be using Pdv for calculating the work done during a reversible adiabatic process ? Why are we using Vdp ? Can some one please explain this ? (P.S. I'm taking an introductory course on ...
2
votes
0answers
59 views

Connection: Work on dipole <-> optical absorption

If I consider a two-level system with a ground and an excited state, I can compute the instantaneous rate at which work is being done on the dipole $\mu(t)$ by an electric field $E(t)$: $\dot{W} = ...
1
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0answers
28 views

work done in observer frame

I had a few questions. 1) Is work done independent of the refrance frame? 2) Suppose a cart-A with rough surface is accelerating with an acceleration a and another cart-B with acceleration b. Now to ...
1
vote
0answers
84 views

Why is no work done by magnetic forces in a uniform B and E field (perpendicular to one another)?

Say $B$ points in the $x$ direction, and $E$ points in the $z$ direction. Assuming a charged particle begins at rest at the origin, its motion will be a cycloid that progresses indefinitely in the ...
1
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0answers
99 views

Is work done on a fluid in a communicating vessel necessarily equal to work done by the fluid inside it?

During the explanation of Pascal's law the argument that work done by a force to move the fluid inside communicating vessel is equal to the work done by the fluid at the other end of the vessel was ...
1
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0answers
128 views

Restrained expansion of a piston/cylinder

Suppose an ideal gas in a piston cylinder has some initial pressure $p_1$, volume $V_1$, and temperature $T_1$. A pin, which holds the piston in place, is suddenly removed, and the gas quickly ...
1
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0answers
153 views

How to solve state parameters using these givens for an ideal gas?

In a thermodynamic turbine using air as an ideal gas, given that you have a known inlet temperature value $T_i$, a known exit pressure value $P_e$, a known inlet and exit velocity $V_i$ and $V_e$, a ...
1
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0answers
116 views

Problem in average height

Let, diameter of cylinder hole of height 30m and diameter 2m filled with water. In a book, when author tried to find out the power for lifting all of the water then he used average height. why is ...
0
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0answers
24 views

Mechanical equivalent of heat => transfer from work W to heat Q

Consider the following experiment to determine the mechanical equivalent of heat $\mu = \frac{\Delta W}{\Delta Q}$ Not seen in the picture is a weight with known mass hanging down the cord. When you ...
0
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0answers
21 views

Work + heat absorbed in a thermodynamic process

The question describes a simple isobaric closed cycle. The temperature is on the y-axis and volume on the other. There are 4 states. The question asks: ''Find the work done on the gas in the cycle and ...
0
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0answers
20 views

Will Energy and Work equal to each other between two closed systems linked by one shareable object?

Two closed systems are linked to each other. Both use same object. In one of this closed systems was spent energy to change physical property of shareable object. After this object transformation, ...
0
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0answers
30 views

The relation between work and time

Work equals the force acting on an object times the distance that object moves. But I am a bit confused about the definition of the distance. is it the distance the object moves under the effect of ...
0
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0answers
24 views

In terms of work, what happens to a negatively charged particle circling around a positively charged rod?

Picture a positively charged glass rod from its end so that if you were to draw it on paper, it would appear as a circle. Now, suppose a negatively charged particle moves in a circular arc, on the ...
0
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0answers
51 views

Electrostatic energy of a distribution of charges

I read, in Gettys' Physics, that, if $N$ charges moves one by one from infinity to a certain point, i.e. the first charge $q_1$ moves from infinity to the arrival point $P$ while the other charges ...
0
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0answers
60 views

Ericsson cycle: what happens if you add more mass?

We recreated the Ericsson cycle using a heat engine apparatus, with air as the working fluid (assumed an ideal gas). During the isothermal compression and isobaric expansion processes, a mass of ...
0
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0answers
55 views

difference between reversible and irreversible entropy

Before I proceed, let me first say I have done research and understand the general idea between the two: summed up crudely reversible happens in a slower continuous manner while irreversible happens ...
0
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0answers
52 views

Does Light have Weight?

If I light a torch and hold it against a wall, will the wall feel any force? If yes, what factors does the magnitude of such a force depend upon? (Area of the wall covered by the beam, intensity of ...
0
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0answers
38 views

Reaction enthalpy-work relationship in a closed piston-cylinder assembly undergoing a chemical reaction

In an closed and insulated piston-cylinder assembly under constant pressure. From first law I should expect $-p(V_f-V_i) = U_f – U_i$ and thus $H_f = H_i$ and $h_f = h_i$. If an exothermic reaction ...
0
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0answers
43 views

How is the Joule normalised acrpss various definitions?

Apologies if this question is a duplicate, I tried searching for this question both on Google and here, but was unable to find an answer. A Joule is defined in various ways, some of them being: ...
0
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0answers
80 views

How to tell direction of work

I think of direction of work as relative to direction of motion, but I got a question of a parabolic ball throw asking the direction work done by gravity and friction over the entire parabola. Since ...
0
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0answers
96 views

Work to Create a Vacuum

I'm trying to determine the amount of work required (in Joules) to create a vacuum of a certain pressure in a tube. A pneumatic cylinder will be used to remove the air from the tube to create the ...
0
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0answers
73 views

Work done on an object from different frames

Consider this situation: A car is moving on a road and applies brakes. The road exerts a force $F$ on the car, due to which the car stops in $S$ meters. Clearly, the work done by the road on the car ...
0
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0answers
471 views

Work done by rolling vs skidding friction force

Two identical bicycles having equal weight riders are traveling along a level road adjacent to each other with the same non-zero velocity. Bike A, (the "skidder"), applies the rear brake strongly ...
0
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0answers
169 views

Collision of two deformable bodies - limitation of work-energy theorem

I am attempting to model the impact of a deformable body (clean, dry sand characterized as a continuous fluid) with flexible diaphragm (in this case a sheet of rubber). Assuming that this is a closed ...