All Questions
32
questions
4
votes
2
answers
2k
views
Why is potential energy defined for only a conservative force? [duplicate]
I want direct answer for this and some interpretation with example.
why do we need conservative force to define potential energy?
what is wrong with non-conservative force and other? I have seen many ...
- 93
2
votes
2
answers
282
views
Work done on an object whilst lifting it
Imagine to lift an object with mass $m$ from height $h_1$ to height $h_2$ and neglect the friction with air. How much work have you done on the object?
My answers (big doubt in the second one!):
...
- 1,319
2
votes
1
answer
2k
views
Is total mechanical energy always equal to maximum potential energy?
Am I correct in stating this: When initial velocity of an object is $0$ then the total mechanical energy will always be equal to the maximum potential energy (with maximum height or displacement) (...
- 23
2
votes
1
answer
870
views
Separating the potential energy of a system of particles.
Assuming all forces derive form a conservative source and that all forces observe the strong form of the third law, how do we arrive at the following equation?
\begin{equation}
V=\sum _i V_i+\frac ...
user58536
1
vote
3
answers
9k
views
Why can't we define a potential energy for a non-conservative force? [closed]
We could define potential energies for non-conservative forces too and then we could conserve it with kinetic and potential energy as we know it. But no one does that. Why is this? Please explain. Any ...
- 913
1
vote
2
answers
164
views
A simple doubt regarding spring potential energy
A conceptual problem. Suppose we have a spring whose stiffness constant is $k$. The spring is attached to a wall and the other end is fastened to a block. If we pull the block by an external force ...
- 882
1
vote
3
answers
395
views
Defining potential energy in Taylor's Classical Mechanics
I'm trying to understand this sentence in introducing potential energy in John Taylor's book:
If all forces on an object are conservative, then can define a quantity called potential energy, $U (\...
- 753
1
vote
2
answers
163
views
Relation between field and Potential energy of a body
I have read that if a body is in a field and is
1. moved in a direction opposite to the direction of a field, its potential energy increases.But why does it increase?
2.Also, if we move the body in a ...
- 597
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
1
vote
1
answer
824
views
Work done for conservative forces is path independent Proof
So I’m looking at the proof for work that is path independent.
There is a line were the integral
Partial derivative V dr from r1 to r2 becomes
Partial derivative V r’ dt from t1 to t2
I’m a bit ...
1
vote
2
answers
380
views
Why is the work done by a block into a spring the same from the work done by the spring on the block?
In the following situation:
A 700 g block is released from rest at height h 0 above a vertical
spring with spring constant k = 400 N/m and negligible mass. The block
sticks to the spring and ...
- 493
1
vote
1
answer
97
views
Is it possible that the particles can be brought by some external agency without changing the kinetic energy? [duplicate]
I am a student and I've been studying a physics book. There is one statement in the solution of one question (regarding calculation of Potential energy) which is confusing me. It states that:
If ...
- 23
1
vote
1
answer
308
views
Potential of conservative generalized forces
In Gregory's Classical Mechanics there's a proof that when a standard system is conservative, the generalized forces $Q_j$ can be written as a potential. But I can't seem to explain some steps in the ...
- 13
1
vote
0
answers
120
views
Are principle of virtual work and principle of minimum potential energy same? And how is it related to Calculus of variation?
I am studying Finite element method and Classical Mechanics. I have come across three important terms
Principle of virtual work (found in Classical Mechanics)
Principle of minimum potential energy (...
- 11
1
vote
1
answer
209
views
Meaning of "a force that derives from potential energy"
In mechanics course, when the idea of equilibrium was introduced they included the idea of a force that derives from potential energy which is the force $F$ which is related to the potential energy $...
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