All Questions
8
questions
5
votes
1
answer
127
views
Net force on the side of a jar
A round conical flask is filled with water of a depth $h$. The radius of the upper water surface is $R_1$ and that of the lower
surface is $R_2$.
What is the net force that the water exerts on the ...
- 1,043
2
votes
1
answer
132
views
If I know the average value over a radial cross section, can I compute the average value over a disk (assuming radial symmetry)?
Let's say that I am trying to calculate the average velocity of a fluid through a pipe and I only know the average velocity of a cross-section through the center, can I find the average velocity in ...
- 300
3
votes
2
answers
236
views
Centroid and "Centre of mass"
I thought that the centroid was also the point at which the area in all directions was net 0. Aka area above the cenrroid was the same area as below.
But for a triangle everything I can see seems to ...
- 165
1
vote
1
answer
3k
views
Calculate moment of inerta of cylinder along central diameter using inertia tensor
how do I find the moment of inerta of cylinder along central diameter which is the one that is $(h^2 + 3r^2)M /12$ ???
I used triple integral and I get
Which I I'm not sure what I done wrong.....
- 169
1
vote
1
answer
301
views
Resistance of a frustum, or a pyramid cut from top
We know that Resistance is given by:
$$R = \dfrac{\rho L}{A}$$
The figure of Resistance is like this, $L$ is perpendicular distance between $A_1$ and $A_2$
I assumed that the area change linearly, so ...
- 7,551
5
votes
8
answers
16k
views
Using polar coordinates to find the area of an ellipse
Considering an ellipse with the $x$ radius equal to $a$ and the $y$ radius equal to b$:$
I figured that some kind of parameterization might be:
$x=a\cos\theta$
$y=b\sin\theta$
and then polar $r^2$...
- 51
4
votes
0
answers
129
views
How to integrate scalar field over quarter torus? Infinite series does not converge.
This seems to be physics question, but the problem just concerns math.
Preface
If one wants to calculate the permeance $P$ of a rectangular bar:
it is an easy task:
$$P = \frac{\mu a b}{L} ~~~~ \...
- 295
2
votes
1
answer
536
views
Moment of inertia of a circle
A wire has the shape of the circle $x^2+y^2=a^2$. Determine the moment of inertia about a diameter if the density at $(x,y)$ is $|x|+|y|$
Thank you
- 1,341