All Questions
112
questions
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36
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Drawbacks of Quasi-Static process for lifting a block
Definition of Quasi-static: A quasi-static process is a thermodynamic or mechanical process that occurs very slowly, allowing the system to remain in a state of equilibrium at all times.
While ...
- 21
1
vote
2
answers
53
views
I am confused about potential energy and work done by a force [closed]
Potential energy is the energy contained in a body due to its position. But I don't understand it because when object falls, PE= mgh and work done by gravity, is - mgh. So what is the difference other ...
- 91
0
votes
2
answers
113
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Paradox? Why does energy conservation appear to be violated in this simple geared system?
While answering a question about gears and levers, I found I could not get the work in to equal the work out in this simple gear system illustrated below:
The gears are set up to replicate a lever, ...
- 6,102
0
votes
0
answers
35
views
Change in Work-Energy Theorem
We have Work-Energy Theorem as follows:
$$W_c +W_{nc} + W_{ext} = ΔK$$ $-(1)$
, where $W_c$ = work done by conservative forces,
$W_{nc}$ = work done by non-conservative forces, $W_{ext}$ = work done ...
- 349
0
votes
4
answers
149
views
Work and Energy Theorem - Theoretical Question
The work energy theorem states that for a given object
∆ Kinetic Energy = Work done by all forces ( Conservative, Non Conservative, External )
Here ,
Suppose if ∆KE = 0 , Potential energy has changed
...
0
votes
1
answer
61
views
Conservative force and change in the mechanical energy
Why is work done by a conservative force equal to change in the potential energy only? Why doesn't it account for all mechanical energy, what about kinetic energy?
0
votes
1
answer
48
views
Work And Energy: Conceptual Potential Energy Doubt
Our teacher told us that objects store potential energy in them according the position of the object above the ground because of gravitational force.
Like we are holding a box up and it stores ...
2
votes
2
answers
120
views
Potential energy of external force
The potential energy is a property of a system, being defined only for internal conservative forces. From the work energy theorem, we have
$$W_{ext} + W_{\text{internal cons. forces}} = \Delta K $$
We ...
0
votes
6
answers
287
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Does potential energy actually exist? Or is it just a useful mathematical model? [closed]
The title basically covers it. I've actually thought about this question for a while now, and I am still not sure if I have a definitive answer. Most potential energies seem to just be the work that ...
- 183
-3
votes
1
answer
84
views
Why Doesn't the Amount of Work Determine the Elastic Potential Energy in Springs and Gravitational Potential Energy? [closed]
Why isn't the amount of work done on the spring the determining factor for the amount of elastic potential energy stored in a spring?
I learned that the change in potential energy is a result of the ...
- 53
0
votes
2
answers
55
views
Work done by gravity confusion
Say we had an object at height $h$ in a gravitational field, and of mass $m$, its GPE would equal $mgh$, now say we dropped it and it fell a distance of $h$, the work done on the object would be equal ...
- 195
0
votes
3
answers
91
views
Where does the energy goes if the force is parallel to the displacement? [duplicate]
So, we all know that if force is perpendicular to the displacement, then work done is 0. But to generate force, I have to use up some of my energy. Had the angle not been perpendicular, my energy ...
1
vote
1
answer
46
views
First principle of thermodynamics with kinetic and potential energies
Edit: Sometimes the first principle is stated as $Q+W=\Delta U\;+\Delta K\;+\Delta P$ (1). I assumed that the expression comes from the more elementary principle $Q+W_{total}=\Delta U$. On the one ...
- 11
0
votes
3
answers
88
views
Consolidating two ways to calculate work
I was wondering if I could get some help closing some fundamental gaps in my intuition of work, as it relates to force and distance travelled.
Scenario
Say we pull a 1kg box along the ground. We pull ...
- 163
1
vote
1
answer
91
views
Kinetic and Potential Energy of a multi degree of freedom (MDOF) system
Consider the following MDOF system:
$M\ddot x+Kx=F$
where $M$ and $K$ are the mass and stiffness matrix respectively, and $x$ and $F$ are the displacement and force vectors.
How can one determine the ...
- 15