All Questions
Tagged with definition forces
44
questions
112
votes
6
answers
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Are Newton's "laws" of motion laws or definitions of force and mass?
If you consider them as laws, then there must be independent definitions of force and mass but I don't think there's such definitions.
If you consider them as definitions, then why are they still ...
- 3,043
11
votes
4
answers
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Define Pressure at A point. Why is it a Scalar?
I have a final exam tomorrow for fluid mechanics and I was just looking over the practice exam questions. They do not provide solutions. But pretty much I have to define pressure at a point and also ...
- 1,158
45
votes
3
answers
8k
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History of interpretation of Newton's first law
Nowadays it seems to be popular among physics educators to present Newton's first law as a definition of inertial frames and/or a statement that such frames exist. This is clearly a modern overlay. ...
user4552
3
votes
6
answers
2k
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Mathematical Reasoning for Fluid Pressure as a Scalar
This question from a while ago and answers/comments to this question from earlier today both make heavy mention of the fact that fluid pressure is a scalar. Although this information was surprising ...
- 2,983
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votes
11
answers
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Why does work depend on distance?
So the formula for work is$$
\left[\text{work}\right] ~=~ \left[\text{force}\right] \, \times \, \left[\text{distance}\right]
\,.
$$
I'm trying to get an understanding of how this represents energy.
...
32
votes
15
answers
6k
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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" ...
- 725
34
votes
5
answers
65k
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Why is the potential energy equal to the negative integral of a force?
Why is the potential energy equals to the negative integral of a force? I am really confused with this negative sign. For example, why there is a negative sign in the gravitational potential energy ...
- 736
8
votes
4
answers
1k
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What exactly is $F$ in $W = \int_{a}^{b} F dx$?
I am trying to teach myself some basic physics, here is something I do not really understand about the definition of work:
When moving from $a$ to $b$ (in one dimension), the work done is defined to ...
- 183
35
votes
4
answers
4k
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The physical definition of work seems paradoxical [duplicate]
So this is possibly a misunderstanding of the meaning of work, but all the Physics texts, sites, and wiki that I've read don't clear this up for me:
In the simplest case with the simplest statement, ...
- 1,229
9
votes
2
answers
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Why is Newton's third law known as *weak law of action and reaction*?
This link shows the extra requirements for strong law of action and reaction. Why is Newton's third law known as weak law of action and reaction? Is the strong law of action and reaction not Newton's ...
- 2,754
8
votes
5
answers
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 \...
- 460
3
votes
7
answers
2k
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Work done when lifting an object at constant speed
A previous post (What Is Energy? Where did it come from?) defines work qualitatively as "a process in which energy is transformed from one form to another form". And mathematically, work is ...
20
votes
3
answers
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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 ...
- 1,295
10
votes
4
answers
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Does the displacement in the definition of work correspond to the displacement of the object or the point of application of the force?
Work is defined as
$$W = \vec{F}\cdot\vec{s}$$
But what what exactly is $\vec{s}$? Is it the displacement of the body on which the force is being applied? Or is it the displacement of the point of ...
- 2,770
8
votes
4
answers
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The elusive difference between force and impulse
Impulse is defined as the product of a force $F$ acting for a (short) time $t$, $J = F*t$, and that is very clear.
What I find difficult to understand is how a force can exist that doesn't act for a ...
user59485