All Questions
22
questions
3
votes
4
answers
1k
views
Can a proof of the work-energy theorem be made, that doesn't use Leibniz notation to cancel differentials?
I've been doing some reading, and even though many people say different things, i think i'm pretty confident in saying that we can't treat differentials as fractions. In some scenarios it works out (...
- 305
0
votes
1
answer
1k
views
Infinitesimal work
I am a newbie in Physics (Senior on highschool) and our teacher wrote in a proof
$$\dfrac{dK}{dt}=\dfrac{dW}{dt},$$
where $K$ is the Kinetic energy of a body and $W$ is the Work.
So now that I am ...
- 103
1
vote
3
answers
121
views
Bounds of Integration (with respect to something that is not time)
I have been reading Richard Feynman's lectures and came across an interesting proof regarding the Earth's gravitational force. At one point in the proof, Feynman uses the following the integral:
$\...
- 954
0
votes
2
answers
294
views
Line integral confusion
Hi , so I was solving this example . I have no problem in calculation . But at the end of it , when they asked about the closed line integral , I wondered how did the line integral on both paths be ...
user65035
4
votes
2
answers
3k
views
Why dont you take derivative of force in definition of power ? P=F.v
The derivative of work is $\bf F\cdot v .$
$$P(t)= \frac{\mathrm dW}{\mathrm dt}= \mathbf{F\cdot v}=-\frac{\mathrm dU}{\mathrm dt}\;.$$
But why not $$\frac{\mathrm{d}\mathbf{F}}{\mathrm{d}t}\cdot \...
- 105
-2
votes
2
answers
103
views
Find $\oint xdx+2ydy+3zdz$ on the line segment formed by points $A(1,0,-1)$,$B(2,5,-1)$ [closed]
Find $\oint xdx+2ydy+3zdz$ on the line segment formed by points $A(1,0,-1)$,$B(2,5,-1)$
My approach:
First I find the line segment formed by $A,B$ which is $\vec l(t)=\vec{OA}+t\vec{AB}=(1,0,-1)+t(1,...
- 107
0
votes
2
answers
304
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Is the Fundamental Theorem of Calculus really applicable to the definition of work?
When the force $F$ on an object is not constant, then the work it performs is defined as $$W = \int_{x_0}^{x} F(X)dX.$$
Now, the Fundamental Theorem of Calculus states that
$$\text{If}\,\,\, f(x) =...
user36790