All Questions
Tagged with definition forces
180
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What does the $F$ in Newton's second law equation mean?
This is a super simple question: does $F$ represent the net force exerted on an object or the force it exerts on another object as a result of momentum? Say a ball is rolling. In this specific ...
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4
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What are internal and external forces?
what is internal and external force? How do I decide what forces are internal and external?
in work-energy theorem and conservation of mechanical energy, do we consider internal, external, or both ...
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3
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Why isn't work a state function?
I've heard the example, that work is path dependent. But whether I climb a mountain directly or in serpentines, in the end it's the same amount of work, with the one difference that it takes me longer ...
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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 ...
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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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What exactly is force - apart from "the ability to do work"? [duplicate]
Does force - any kind - have an identity of its own apart from the set of effects it brings about? Or is it just "that which" ... "causes"; does this and that, makes certain ...
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1
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66
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What is difference between normal force and reaction force? [duplicate]
according to my book the perpendicular component of reaction force is called normal force when there is contact between two bodies. I can not understand that how for example when we jump we pushes the ...
user379089
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What is normal force and when it acts?
what are contact forces and according to: https://www.physicsclassroom.com/class/newtlaws/Lesson-2/Types-of-Forces
it says there are 6 types of contact forces. I am having doubt with applied force and ...
user379089
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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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Difference between moment and couple
What is the exact difference between a moment and a couple? In some YouTube channels and books, they say the moment of a force produces a translational as well as rotational motion whereas the concept ...
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5
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What is equilibrium position in a pendulum? Will there be only one equilibrium position in the motion of a pendulum?
Equilibrium position of a pendulum is defined as the position where no external force acts on the body and if no force is applied, it remains at rest. In the image, isn't gravity acting everywhere, ...
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Relation between Force and Potential in a relativistic context
In a relativistic context we define the four-force as, $$\frac{\mbox{d}}{\mbox{d}s}p=F$$ In the particle frame the four-force must have the form $$F=\left(0,\ \mathbf{f}\right)$$ As it must be ...
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Definition of stress (Mechanical Properties of Solids)
See, it's a simple question.What exactly is stress? Is it the restoring force applied by the body in reaction to deformation force or is it the deformation force itself? I had this doubt because in ...
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2
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Are the definitions of force and acceleration circular? [duplicate]
Force is defined by acceleration , and acceleration requires the determination of" inertial frames".
But an inertial frames also requires the knowledge of forces which requires measuring ...
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What is actually the clear, precise and world-wide accepted definition of TENSION FORCE?
This is a long post, but only because I have explained the scenario very very clearly,90 percent of this post is explaining you a simple situation,my doubt is only 5-6 lines at the very end of this ...
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How can work be a function of position when non-conservative forces don't act the same way at each point?
My textbook and wiki/online articles all claim that work is given by the integral
$$W=\int_\gamma\vec{F}\boldsymbol{\cdot}\text{d}\vec{s}$$
where the $\text{d}\vec{s}$ is some infinitesimal step along ...
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What is the difference between work done against gravity and work done by gravity?
Work done "BY" a force,from my understanding,is:
•positive when the direction of displacement is same as the direction of force.
•negative when the direction of displacement is opposite to ...
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Motivation for definition of work [closed]
Why do we take the dot product in the work energy theorem? Consider the integral
$$\int\vert\vec F\vert\vert d\vec r\vert$$
Why don't we define this to be work done for example, instead of $\int\vec F\...
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${}$Conservative and Non-Conservative Forces
For work done by conservative forces ($W = F.S$), we consider $S$ as the displacement and not the actual path travelled. However for non conservative forces we consider the total path length and not ...
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2
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605
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Why does small work done mean $dw=f.ds$ and why not $dw=df.ds$ and why not $dw=s.df$? [duplicate]
Work, power and energy questions.
Why does small work done mean:
$$dw=f.ds$$
and why not:
$$dw=df.ds$$
and why not:
$$dw=s.df \ \ ?$$
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What actually is impulse?
In my textbook it is mentioned that “impulse is used to get an idea of about the change in dynamical state of a moving particle”,but what does impulse actually mean?
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Work done by non-continuous force
How work done is really understood?
I know that $W=F\cdot d$. I am interested in the meaning of force here i.e.
Is it a continuous force applied till displacement? like the case of pulling trolley ...
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Definition on type of work [closed]
A man carries a bag hanging it in his hand and he moves horizontally. The bag does not move up or down. What is the work done on the bag? The man gets tired after some time of the movement. Why?
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The definition of Electric field?
In Raymond Serway's physics textbook, the definition of the electric field vector, was that it's force vector acts on a positive test charge, given as force divided by the test charge:
$$\...
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Are Newton's laws just definitions?
I have read a bunch of articles online regarding my question but none have helped.
Newton's Laws:
In an inertial reference frame, an object's momentum doesn't change unless the object is acted upon ...
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3
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Meaning of "$=$" in $\vec{F}=m\vec{a}$ (for example)
I don't understand how the two could really be one and the same. E.g. we can exert forces $\vec{F}$ and $-\vec{F}$ on a body and it's acceleration will not change. I don't think it makes sense to say ...
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607
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Why is torque defined as $\vec{r} \times F$?
Here I cannot convince myself myself that it is units because the torque is defined to be in units of Newton meter is a reiteration of the law stated above. Why was it not $r^2 \times F$ or $r^3 \...
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Formula for work done for both conservative and non-conservative force are different?
We know that the formula for Work Done by an constant force is
W.D = Force x displacement x (cosine of angle between force and displacement).
Situation: A mass m travels 10 meters towards +ve axis ...
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Even at an elementary level, can "force" be defined as "cause of motion"?
In Leçons de physique (Lessons On Physics) (auth. Perez, De Boeck editor) can be found this informal definition of force: "forces are what cause motion".
Is this definition accurate?
What I ...
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How exactly IS Newton’s second law verified experimentally?
In R. Shankar’s “Fundamentals of Physics : Vol 1” while discussing Newton’s Second Law of Motion, Prof. Shankar raises the question : how do we know Newton is right? I quote from the book :
Take ...
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What is the fundamental definition of force?
As I pick up more physics I see that the definitions of force commonly provided in books and classrooms are misleading.
"A force is a push or pull." This seems to be a "correct" ...
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What is actually weight?
When a book is kept on the table than gravity of earth is attracting the book downwards and gravity of book attract earth this is action reaction pair
Now here are two more force acting normal ...
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How to know what force to plug in for work?
Suppose I have a positive charge $+Q$ at some point, and I want to see how much work I need to do to bring a negative charge $-q$ to a distance $r$ from that point. The direct calculation is done via ...
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What is the formula for the force of friction as a vector?
The formula I've grown up with is $F_{fr} = \mu F_{N}$, where
$\mu$ is the coefficient of friction between the object and the surface
$F_{N}$ is the normal force of the surface acting upon the object
...
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Can (and should) wifi internet be considered a force? [closed]
I've recently been using my wifi internet, for the last few years and have been enjoying it very much. I am able to communicate with my family across the globe in mere seconds, it's obviously a marvel ...
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How can an object do work?
I read in many sites that the concept of mechanical energy is the ability of an object to do work, but how can an object do work? Isn't it rather the force applied to that object the one that produces ...
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Is "force" and "exerting a force" the same or different things?
Is "exerting a force" and "force" the same or different things?
Either it your answer is "same" or "different" give an explanation for this.
How this doubt came ...
user316791
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Clarification on the displacement in the definition of Work
I'd like to ask a question about work. The definition of work gives us a way to calculate the work done by a force along a path but in practice it's not always clear what path to take in consideration....
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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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Measurement of force
According to Newton's Second Law,
$F=ma$
which is based on the fact that force is proportional to acceleration for a constant mass.
But how will someone measure force to confirm this?
Suppose one ...
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Proving if a force is conservative and non-conservative
recently I have studied conservative forces and non-conservative forces in halliday book and while doing some exercise I saw some questions asking for proving if a force is conservative so after doing ...
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What does potential energy really mean?
I have a lot of doubts regarding the potential energy definitions
First of all,I would try to express my Understandings(they might be wrong)regarding the issue
I was told that if Work done on a body ...
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Is Newton's second law definition of force, or experimental statement? [duplicate]
I usually hear explanation of the second law like this:
If you apply twice as much force, it doubles the acceleration.
When the same force is applied, if the mass is doubled, the acceleration becomes ...
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684
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Circularity In Definition Of Force?
So my college physics book defines a force as a push/pull, but mainly a vector quantity, having both magnitude (strength) and direction.
Yet it also defines the unit of a Newton, as THE FORCE, ...
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Why is electromagnetism considered a non-contact force?
The four fundamental forces (gravity, the strong force, the weak force, and electromagnetism) are all supposed to be non-contact forces. Yet, electromagnetism governs all contact forces between ...
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How does one prove that the conservative force $\vec{F}$ is equal to the negative gradient of the potential $V$?
I have a grasp of the gradient theorem, and I understand that if we let $\phi$ be a function such that $\vec{F}=\nabla \phi$, and $V(\vec{x})$ be the potential at $\vec{x}$, then
$$-\int _C\vec{F}d\...
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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
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Why is work done force times displacement? [duplicate]
Why is work done the product of force and displacement? Why not force and time?
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376
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Why is $f = -\frac{du}{dx}$?
I am studying Newtonian Mechanics and I am familiar with single variable calculus.
I came across the concept of conservative and non conservative forces and potential energy. Here is what I understand:...
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Why do we multiply $\cos θ$ in the formula for work? [duplicate]
I know that the formula for work, $W = FS\cos\theta$, where $F$ is the applied force, $S$ is the displacement of the object and $\theta$ is the angle between the applied force and the displacement of ...
