All Questions
66
questions
4
votes
3
answers
614
views
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 ...
- 211
1
vote
1
answer
56
views
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 ...
- 97
0
votes
2
answers
102
views
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
1
vote
2
answers
1k
views
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 ...
- 57
-1
votes
2
answers
99
views
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\...
0
votes
1
answer
76
views
${}$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
vote
2
answers
605
views
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:
$$dw=s.df \ \ ?$$
1
vote
2
answers
198
views
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 ...
- 101
-1
votes
3
answers
60
views
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?
0
votes
1
answer
635
views
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 ...
- 1
0
votes
1
answer
44
views
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 ...
- 163
4
votes
3
answers
815
views
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 ...
- 179
1
vote
3
answers
112
views
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....
- 410
4
votes
2
answers
929
views
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 ...
- 45
0
votes
2
answers
362
views
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 ...
- 452