All Questions
275
questions
1
vote
1
answer
66
views
Calculating deflection on a beam
This is for a hobby project, and to learn a little about elasticity along the way.
I have a triangle wedge comb piece of decreasing width and angle for which the cross section is shown here:
For each ...
- 326
1
vote
0
answers
96
views
Covariant derivative of a Riemann tensor
I'm trying to calculate the covariant derivative of a Riemann tensor, and I'm using the following way, but there is some problem in my calculations because my calculations do not match with the ...
- 11
0
votes
0
answers
29
views
Algebraic varieties associated with (simple) "string" constructions
It is relatively well-known that any arrangement of points that can be constructed with a straightedge and compass can also be constructed with an unstretchable string (of arbitrary length, negligible ...
- 131
4
votes
1
answer
70
views
Modeling Nanotubes Geometry
In various references, we see the construction of unit cells of carbon nanotubes (CNTs) from chiral and translational vectors.
The chiral vector is given as:
$$\vec C_h = n\vec a_1 + m\vec a_2$$
...
- 3,789
1
vote
0
answers
48
views
Clarification Regarding Solid Angle
I am studying Zangwill's Modern Electrodynamics but I'm having trouble following an argument he makes about solid angles in preparation for deriving the integral form of Gauss's law.
He defines the ...
- 309
0
votes
0
answers
33
views
Rearranging trigonometric equation for low speed vehicle turning geometry
I have a set of equations that describe the geometry of a vehicle in low speed turning (a single track vehicle with the assumption that the tyres go in the direction they are pointing). A constraint ...
0
votes
1
answer
36
views
Precisely defining the overlap depth, or deepest point of overlap, for ellipsoids and spheroids
I was wondering if there is a robust mathematical definition for the 'deepest point of overlap' of ellipsoid (or, equally as good, spheroid) 1 that has overlapped with ellipsoid 2. For non-overlapping ...
0
votes
2
answers
120
views
Explain how shall we get a direction at a point on the surface of earth other than north pole using magnetic compass [closed]
The Qibla Compass can give the direction towards "some points on earth" other than north pole, eg : Mecca.
Wikipedia first paragraph, last two lines :
To determine the proper direction, one ...
- 556
1
vote
1
answer
371
views
whats happening when i do arctan? Mistake or wrong in calculator
I have a problem in a solids course about mohrs circle and its principal forces.
I have solved to its last part and it all checks up when putting the right angle theta which makes the shear stresses ...
- 19
2
votes
0
answers
53
views
Optical path of a light ray reflected from two mirrors and into a pinhole camera
I have been staring at this problem for longer than I would like to admit.
I am trying to determine the path of a light ray from an object that is reflected from two plane mirrors and into the ...
- 21
0
votes
0
answers
42
views
How can I find the point of balance of an half ellipsoid with the equation $\frac{x^2}{a^2}+\frac{y^2}{b^2}+\frac{z^2}{c^2}=1,\:x\ge 0$
How can I find the point of balance of an half ellipsoid with the equation
$$\frac{x^2}{a^2}+\frac{y^2}{b^2}+\frac{z^2}{c^2}=1,\:x\ge 0$$
As point of balance I mean the point on the surface it stays ...
0
votes
1
answer
146
views
Calculate position of bouncing ball based on arbitrary time value
Usually, when you make a bouncing ball in any programming language, you have an X and Y value that updates over time, as well as an x velocity and y velocity, whose signs flip when the ball hits the ...
- 3
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
1
vote
0
answers
56
views
Doubt about Malus Theorem. (Optics)
I'm reading the text "General theory of rectilinear ray systems"
By E. E. Kummer. (http://neo-classical-physics.info/uploads/3/0/6/5/3065888/kummer_-_rectilinear_ray_systems.pdf). I'm new in ...
- 342
1
vote
1
answer
93
views
Problem with the geometry of two balls inside a jar
lets say we have 2 balls inside a jar with radius 1.5, I am trying to calculate the torque with respect to the point of contact of the left ball with the jar.
so far I have that the weight of the ...
