All Questions
Tagged with definition forces
180
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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 ...
- 179
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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 ...
1
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2
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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:
$$dw=s.df \ \ ?$$
5
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6
answers
2k
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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?
2
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4
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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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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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1
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635
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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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1
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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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