All Questions
14
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In physics, what is the difference between a fact and a definition?
For example, I came across this statement:
"It is a fact that the components of force are derivatives of potential energy, but it is not a definition."
What does this statement mean?
I ...
- 77
2
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1
answer
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Definition of generalized force in Lagrangian formalism
In some texts (e.g. Taylor's Classical Mechanics), the generalized force is defined to be (I'll simplify to one particle in one dimension for ease of notation): $Q \equiv \frac{\partial{L}}{\partial{q}...
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1
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Conditions for a force to be conservative - Does the second condition imply the first? [duplicate]
John Taylor's Classical Mechanics says this...
I was wondering if the second condition already implies the first? I mean, are there situations where the first condition is violated even though the ...
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1
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129
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What (pedantically) defines a "central force", as in "central force law of areas", etc.?
A typical description of a central force is found here Lecture L15 - Central Force Motion: Kepler’s Laws (pdf).
"When the only force acting on a particle is always directed to wards a fixed ...
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4
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3
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463
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What is the meaning of external force in the Newtonian force equation?
I came across the following in Goldstein's Classical Mechanics book, section 1.3.
In a system of particles, the equation of motion for the $i$'th particle is to be written
$$ \sum_j F_{ji}+F_i^{(e)}= \...
user310684
1
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1
answer
103
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What is a physically precise definition of mass in Newtonian mechanics? [duplicate]
How do we get to know the concept of mass in Newtonian Mechanics?
Like, from Newton's Second Law of motion we get : $\frac{d\vec P}{dt} = \vec F$ from here, $m\frac{d\vec v}{dt} = F$, defining $\frac{...
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1
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Positional is not equivalent to conservative in dimensions greater than one
I've just started writing dynamical systems and I was trying to find an example to show that if we are in a $2$ or $3$ dimensional real space "positional do not implies conservative".
In ...
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2
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2
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What is meant by "inertial forces", in contrast to the "resultant force"?
For example, in the Wikipedia page on Reynolds number it is said:
The Reynolds number is the ratio of inertial forces to viscous forces within a fluid..
In explanations of the Reynolds number, it is ...
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20
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3
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Conditions for a force to be conservative
Taylor's classical mechanics ,chapter 4, states:
A force is conservative,if and only if it satisfies two conditions:
$\vec{F}$ is a function of only the position. i.e $\vec{F}=\vec{F}(\vec{r})$.
The ...
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5
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4
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What's the difference between normal and reaction force?
Learning about forces and frictions at the moment, one things I can't seem to grasp is what is the difference between the normal and reaction force? They both act perpendicular to a surface and away ...
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1
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250
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What is the difference between the applied, external force and the generalized force?
in analytical mechanics, we define the generalized force using the applied force times $dr/dq$. If I want to express the difference between the external and generalized force in words in order to ...
2
votes
1
answer
192
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Is there any special significance of force field in physics?
What is the formal definition of force field? Which is more fundamental force or field? Do field exist in nature (as force do i think as per section 12-1 of Feynman lecture volume 1, and page 8,9 of ...
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A question about central forces
Will a force pointing towards a fixed point but having constant magnitude (and not depending on the distance from fixed point) be a central force?
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Is "Field" a more fundamental quantity or "Force"(in classical mechancis)?
Consider an isolated system consisting of two particles. We can say the two particles are exerting gravitational forces to each other due to their masses. Also we can say each particle has a ...
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