All Questions
Tagged with conventions work
178
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Why is work done by force $+mgh$ in the situation of throwing something up?
If there is a particle at point A(at rest) and a force moves it to point B(Above point A vertically)(final velocity = 0 at this point), the work done by gravity is $-mgh$. This I understand as the ...
- 85
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96
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The sign of Work in Turbomachines point of view
As I know from Thermodynamics work done by the system is negative and equals to $U=Q-W$. In this picture it clearly describes the process in which when we take some pebbles from the piston the system ...
- 15
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103
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Defintion of gravitational potential
I am not much clear regarding the defintion of "gravitational potential":
Is the work done for bringing the unit mass from infinity to that point by, gravitaional force or external force? (...
1
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3
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94
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Gravitational Potential Energy Behavior [duplicate]
I had a question regarding gravitational potential energy and escape velocity. I don't really understand the concept of escape velocity. I have been learning it as the velocity required for an object ...
- 19
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222
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Derivation of the gravitation potential energy and gravitation potential
I have some slight confusing in deriving the gravitation potential energy.
In the image below, it explains that the gravitation potential energy is equal to the work done from infinity to a distance r ...
-1
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3
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78
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Sign of work done by spring force [closed]
Two similar springs P and Q have spring constants $K_p$ and $K_q$ such
that $K_p>K_q$. They are stretched by the same amount. Compare the
work done by the springs. (NEET 2015)
$$W_p=-\frac{1}{2}...
- 347
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5
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246
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Work done in raising an object to a height
When we raise an object to a height $h$, it is said that the potential energy of the object is increased by $mgh$. But isn't the work done by gravitational force $-mgh$?
Then that will essentially ...
- 702
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80
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Confusion in definition of Potential Energy
Potential energy is defined like this. $ΔP.E=-W_{AB}$. This means that the potential energy at point A minus potential energy at point B should equal the negative of the work done by a conservative ...
- 122
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68
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Sign convention of work
I am studying about reversible steady-flow work, and the author of the book states that Taking the positive direction of work to be from the system (work output) the energy balance of a steady-flow ...
- 27
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103
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A contradiction in the derivation of electrostatic potential energy? [closed]
I am a 12th grade high school student with no knowledge of vector calculus and more advanced physics.. so if possible, please try to refrain from using advanced concepts which I do not understand.
...
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407
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Contradiction in Thermodynamic Work and Mechanical work [duplicate]
The first law states that $ \Delta U = Q - W $ where W is the work the system does on the outside. If there is no heat added, the change in energy is equal to the work done. If the work is negative, i....
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Clarification on thermodynamics and mechanics
This is a follow-up question to an answer https://physics.stackexchange.com/a/746974/377012 on this topic. In that answer, what does $W$ refer to? Is it the work done ON the system, by forces OTHER ...
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2
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133
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Work Done By vs Work Done On
Assuming right to be positive, in this question, is the work done by the boy positive or negative? I would think it is negative because the force that the boy exerts is towards the left while the ...
- 568
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143
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Sign conventions pressure volume work
In the first law of thermodynamics, using the convention that work is done on the system by the surroundings,
$dU=Q+W$.
Usually it is written that pressure volume work is $W=-pdV$, where $p$ is ...
- 693
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Sign of reversible work done
Consider a piston such that it is in mechanical equilibrium with its surroundings. If I pull the piston (reversible work) then the work done by me would be positive. If I push the piston, again work ...
