All Questions
Tagged with applications physics
67
questions
-1
votes
3
answers
53
views
How to untangle the ODE $\frac{dx}{dt} = c + \frac{px}{l_0 + pt}$? [closed]
In working on this problem, I came up with the following differential equation:
$$
\frac{dx}{dt} = c + \frac{px}{l_0 + pt}
$$
where $x$ is the dependent variable, $t$ the independent, and all others ...
- 4,450
22
votes
5
answers
2k
views
What do physicists mean when they say something is "not a vector"?
It's common for physicists to say that not every 3-tuple of real numbers is a vector:
“Well, isn’t torque just a vector?” It does turn out to be a vector, but we do not know that right away without ...
- 4,450
8
votes
2
answers
803
views
Negative Numbers in Math & Physics
We say that $-4 < -2$ and that $-3 < 0$ and that $-192 < 24$. I'm aware that there are simple, easily understandable definitions for less than / greater than / equal to e.g. $a < b$ iff ...
- 967
2
votes
0
answers
98
views
Heat from a geothermal well: your take?
Imagine digging a cylinder-shaped (vertical) bore-well of depth $L$ and diameter $r$ ($L\gg r$). The (infinitely thin) cylinder-wall is made watertight and we split the well in half using a kind of ...
- 2,455
0
votes
1
answer
93
views
How taut must a stretchable, horizontally-oriented string be in order for a straight line to approximate the string to within a given margin of error? [closed]
My question deals with a string that can stretch due to its own weight. If the string is allowed to stretch then I'd assume there would always be a bit of a bulge due to gravity.
The only progress I'...
- 865
1
vote
0
answers
31
views
Error while calculating force in 2D flow around a circle
This is statement of the exercise:
In this exercise we consider as example the case of a disk of radius R centered at the origin of coordinates immersed in a fluid of density σ and velocity field $u(x,...
0
votes
0
answers
45
views
Cavalieri's Principle in volume calculation
In petroleum engineering, for easier calculation of the volume underlying a specific surface underground, the irregular surfaces are modeled by an equivalent surface with circular cross sections, ...
4
votes
1
answer
387
views
I've never been so confused (Application of Integral Calculus)
Here's a problem on Application of Integral calculus to find the work done in moving a particle. I was able to 'reach' the 'right answer'. But I'm totally confused and utterly dissatisfied with the ...
- 1,156
3
votes
1
answer
123
views
Strong solutions of SDEs in electrical engineering
I am currently reading about existence and uniqueness theory for stochastic differential equations (SDE). Two of the main concepts are: strong and weak solutions.
I do understand the difference ...
- 319
0
votes
0
answers
524
views
Application of Graph Theory in Electrical Circuits
I've been learning about electrical circuits, and I can see how Graph Theory naturally lends itself well to problems with circuits.
I was wondering what some examples of applications of Graph Theory ...
- 140
1
vote
0
answers
147
views
Finding optimal 2D trajectory on a simple rocket control without air resistance
My problem is as following:
Suppose we have a rocket ship, which is modeled as a point mass(the mass doesn't matter, but we'll assume it's a constant $m_0$ for simplicity).
It can accelerate in any ...
- 111
1
vote
1
answer
208
views
Criterion to see if you can neglect air drag in projectile motion
In physics education you often consider "real world problems" with projectile motion. Most times in introductory courses you neglect air drag. But how can students (knowing nothing about ...
- 987
0
votes
0
answers
92
views
Derive the equations of motion and determine whether angular momentum is conserved..
Suppose that the gravitational force is not given by the inverse-square law, and instead is
$$ F_{grav}=\left(\frac{A}{r^{2}}+\frac{B}{r^{4}}\right)\hat{r}, $$
where A and B are real constants. Derive ...
- 1
0
votes
1
answer
60
views
Interpretation and use of the logarithmic scale for high school students
Often when we discuss on the logarithms in high school we also talk about a scale called logarithmic.
In the he logarithmic scale: the distance from $1$ to $2$ is the same as the distance from $2$ to ...
- 7,814
0
votes
2
answers
130
views
Invertible polynomial that approaches linearity at large x
I need to approximate a function $y=f(x)$ using a small set of constants $a_0…a_n$, ideally where the number of constants can be arbitrarily increased to improve accuracy. $x$ and $y$ are both real ...
