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"head" in the name refers to the Mathematica concept. That was the first account I created. I kept the name.


1d
comment Does “converge” mean intersecting and producing image when we are taking about convex lenses?
Yes, the lens will bend the light rays so they all converge to a single point. To add a wrinkle, I will say that the location of this point will depend on what angle the incoming rays from infinity make with the lens.
1d
answered Does “converge” mean intersecting and producing image when we are taking about convex lenses?
1d
revised What do “ℜe” and “A*” mean?
added 110 characters in body
Jul
29
comment Moment of Inertia and Rotational Dynamics?
@1110101001 angular momentum is different from $mv$, which is usually called momentum, but can be called linear momentum to distinguish it from angular momentum. Describes motion going around a point, and the further away from the point you are, the more angular momentum you have. This is why there is an $R$ in the formula.
Jul
15
comment Using Dynamics to find the Net Force of a object upon two other masses acting upon it
From this I gathered that the main source of confusion was how to add forces acting in different directions to get the net force. Looking at the picture of his work supports this conclusion. Therefore I would say his question is really just about that concept. Now you could say that we should only allow questions when the asker himself is able to identify the specific concept he is having trouble with, but I think that will leave out a lot of potential questions. I think as long as the asker makes a good effort to narrow the scope of the question as much as they can, then its specific enough.
Jul
15
comment Using Dynamics to find the Net Force of a object upon two other masses acting upon it
For what its worth, I don't think this question should be closed, at least not for the reason stated. It's clear that LostAtPhysics showed effort to solve the problem, so it shouldn't be closed for that reason. However, you could object that there is no concept singled out as the topic of the question, but I would say there is: The question says (v2) "Overall I can do questions like these in linear, yet when it comes to this question is stumped me, would be have like a vector (direction) in the final answer?" ...
Jul
15
revised Using Dynamics to find the Net Force of a object upon two other masses acting upon it
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Jul
15
answered Using Dynamics to find the Net Force of a object upon two other masses acting upon it
Jul
11
awarded  Revival
Jul
6
reviewed Leave Open Why can arbitrary two qubit density matrices be expressed in this form?
Jul
1
answered Can the entropy of a part of a closed system become less than the initial entropy of the entire system?
Jul
1
comment Electric field due to an electric dipole at a point on the equatorial line
You can tell the first formula is only referring to the magnitude because the $E$ on the right hand side does not have an arrow above it (as in $\vec{E}$), nor is it bold (as in $\mathbf{E}$). These are two ways of showing something is supposed to refer to a vector. The plain ordinary $E$ just denotes the magnitude of the electric field.
Jun
30
answered Physical meaning of wavelength of a EM Wave
Jun
30
answered Does all of spacetime exist?
Jun
29
comment Solution of the Radial Part of the Schroedinger Equation
I only remember seeing laguerre polynomials when there is a coulomb potential. Are you sure the radial wavefunctions can be expressed in terms of laguerre polynomials when there is no coulomb potential? I would think the spherical bessel functions make more sense, but I haven't done the math. For example, I wouldn't expect the exponential decay in $r$ (as seen in the laguerre solution) if there is no confining potential.
Jun
29
answered Torque Approximations Neglecting Friction
Jun
26
comment Torque Approximations Neglecting Friction
But shouldn't $T_{ex}$ and $T_{approx}$ be the same when $a=0$. How are they different?
Jun
26
comment Torque Approximations Neglecting Friction
Try setting the $a$ equal to 0 instead of .0615 m/s^2 and see if the two torques agree.
Jun
26
comment Torque Approximations Neglecting Friction
But $a$ seems so small compared to $g$. How could such a small $a$ throw your answer off that much? Your answers must be different for another reason.
Jun
26
reviewed Leave Open How can i prove that $\frac{d\vec{p}}{dt} = \vec{F_{net}}$?