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visits member for 3 years, 9 months
seen 11 hours ago

Started programming on a ZX spectrum in the 80's and have moved through Assembly, Turbo Pascal, C++, C#, Fortran. My main area of focus is engineering and scientific computing like numerical methods and 3D graphics.


11h
comment Show that the profile of the hill is a cycloid
So what have you tried? Have you looked at the equations of the rock height? How about looking at how the shadow moves as a function of instantaneous dome slope (at height)?
13h
comment Why is the cross product between two vectors calculated by the determinant of a matrix
What I mean is that the $[\vec{a}\times]$ matrix transforms the $\vec{b}$ vector. For example in a rotating frame $[\vec{\omega}\times] \vec{r}$ returns the rate of change of the components of a body fixed vector $\vec{r}$. The $\times$ takes a vector and turns it into an operator (like a function but in vector space).
17h
comment Why is the cross product between two vectors calculated by the determinant of a matrix
I always look at the cross product as a linear operator $$ \vec{a}\times\vec{b} = \begin{pmatrix}0&-a_k&a_j\\a_k&0&-a_i\\-a_j&a_i&0\end{pmatrix}\begin{pmatrix}b_i\\b‌​_j\\b_k\end{pmatrix}$$
2d
comment What formula connects the moment of inertia and angular velocity?
-1 because although you answered the question, you did not provide additional information that might help the OP in the future. Like the fact that angular momentum above is only valid on the center of mass. Otherwise you have to consider the parrallel axis theorem and the cross terms $ \vec{r} \times m \vec{v}$ from the motion of the center of mass.
2d
comment What formula connects the moment of inertia and angular velocity?
Try to use math formatting. See physics.stackexchange.com/help/notation
Aug
29
comment Calculating the rate at which a car turns
See physics.stackexchange.com/a/99570/392 for how to resolve (or combine) accelerations that follow a path (like a circle).
Aug
28
comment What is a good introduction to integrable models in physics?
Baxter is a dead link.
Aug
28
comment sketching some geometry
See meta.physics.stackexchange.com/questions/4697/… for resource recommendation posts.
Aug
28
comment sketching some geometry
Good question, but not for this forum. Maybe it can be re-opened as a tool recommendation question for drawing sketches. The question would need to be edited. Something similar to math.stackexchange.com/q/40770/3301
Aug
28
comment Trying to make a realistic simulation of 'breaks' (Pool)
Also see ruina.tam.cornell.edu/research/topics/collision_mechanics/…
Aug
28
comment Trying to make a realistic simulation of 'breaks' (Pool)
See real-world-physics-problems.com/physics-of-billiards.html
Aug
27
comment A ball rolling in a bowl
How is the tilt and slope different? Also, what is your question here?
Aug
27
comment How to find a vector normal to a cylinder in cylindric coordinates?
This question appears to be off-topic because it a simple search can yield the answer. See en.wikipedia.org/wiki/…
Aug
26
comment At the instant of release of an object from rest. Is the only force that can act its weight?
See here on how to apply the equations of motion on a point away from the center of mass.
Aug
26
comment At the instant of release of an object from rest. Is the only force that can act its weight?
This question should not close as the OP has some confusion on how to apply the equations of motion.
Aug
26
comment At the instant of release of an object from rest. Is the only force that can act its weight?
Actually there is movement because AB goes from horizontal initially to vertical when $\omega = 2.4$
Aug
26
comment A triangle in static position
A guess won't cut it. Show us your work.
Aug
26
comment Topple a mass standing still
@Floris As far as the cm location, maybe that is what $x$ means in the OP. I asked about it and didn't get a satisfactory answer.
Aug
26
comment Topple a mass standing still
@Floris yes I should change the traction forces but since they don't enter into the torque balance it does not change anything. Also $N_2$ is included to show what happens when the box is not toppling.
Aug
26
comment Topple a mass standing still
It is not clear but the OP assumes a flat ground, without a corner at $x$.