All Questions
Tagged with classical-mechanics work
214
questions
67
votes
15
answers
22k
views
Why is ascending some stairs more exhausting than descending?
I have been asked this question by school kids, colleagues and family (usually less formally):
When ascending a flight of stairs, you exchange mechanical work to attain potential Energy ($W_\text{...
- 831
1
vote
1
answer
285
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Is angular work equivalent to linear work?
When considering the definition of angular work, I assumed that it should reduce to the definition of linear work in order to tie in quite nicely with conservation of energy. However, further ...
- 348
0
votes
1
answer
371
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When calculating work in a line integral is the work done time independent?
The paramaterization of a curve when calculating the line integral is independent of the paramterization, it depends on path taken in the curve. My intuition is failing me, since it was said that by ...
user86411
1
vote
2
answers
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Why can we not set each applied force equal to zero?
With reference to page 17 of "Classical Mechanics" by Goldstein, Safko and Poole, the small paragraph after eq. 1.43,
$$\sum_i \mathbf{F}^{(a)}_i \cdot \delta \mathbf{r}_i ~=~ 0.\tag{1.43}$$
I do not ...
- 21
1
vote
1
answer
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Virtual work of a moving surface on a particle constrained to it
I've only just begun reading through Goldstein's Classical Mechanics. This section is on D'Alembert's Principle and Lagrange's Equations. The following quote is from the beginning of the section.
...
- 569
2
votes
2
answers
261
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Work done by static friction during rolling while slipping?
I'm a bit confused on whether, during slipping while still rotating, friction does work on the object. I know there are multiple questions on SE that address the rolling case, but this is very ...
- 1,177
-1
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4
answers
5k
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Does a force do work if the direction of displacement is not in the direction of it (except the case of 90 degree)?
From Work (Physics) - Wikipedia:
In physics, a force is said to do work if, when acting, there is a displacement of the point of application in the direction of the force.
According to the ...
- 5,819
2
votes
1
answer
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How to prove force is conservative?
How do I prove whether a force perpendicular to the motion is conservative and $\mathbf{F}=\mathbf{F_{0}}\sin(at)$ conservative, where $\mathbf{F_{0}}$ is a constant vector.
I knew that for a force ...
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-1
votes
1
answer
58
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Conservation Of Mechanical Energy [closed]
I just observed that ,
Mechanical Energy(E) = Potential Energy(U) + Kinetic Energy(K)
Now ,
from simple algebra,
E-U=K
Also we know that Kinetic Energy K is always positive.
I ...
- 564
-1
votes
3
answers
10k
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In the equation "Power=Force . Velocity", if velocity is considered constant, how can force exist?
Power(P)=Force(F) . Velocity(V)
"In the straightforward cases where a constant force moves an object at constant velocity, the power is just P = Fv. In a more general case where the velocity is not ...
- 439
5
votes
3
answers
352
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How the definition of work is derived from Noether theorem?
I cite the following phrases from an answer to the Phys.SE question Why does a force not do any work if it's perpendicular to the motion?
...an alternative would be to treat the work-energy ...
user143115
1
vote
3
answers
594
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What is the correct way to estimate the work done by a climber?
My teacher gave us a worksheet with word problems and their solutions. It is in German, so I have tried my best to translate it to English:
A 26 year old man climbs Mount Everest (8848 m) in only 8 ...
- 19
0
votes
1
answer
87
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Force, displacement and work
Can it still be called work if the force exerted is in the same direction with the displacement of the body, however, the force is so little that it actually does not do anything on the body while ...
- 13
0
votes
1
answer
33
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Work of a force
What does the work of a force really represent ? Isn't there any good explanations describing the idea behind this notion, when I first saw it, it felt like the work is equal to the force vector doted ...
- 103
0
votes
3
answers
129
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Do I apply any force towards right when I move an object towards right through air (neglecting air friction)?
I am holding an object in my hand fully extended in air. If I move it towards right , will I have to apply any force in the direction of motion (neglecting air friction)?
In my book they say work ...
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