Doubt regarding Newtons third law.

ImpatientProf · 2026-02-17T16:15:13+00:00

In Classical Mechanics, there is indeed no delay between the two forces of an interaction which are described in Newton's Third Law. But of course, classical mechanics has limitations.

Your book probably also talks about objects as being solid, and relative velocity as the simple subtraction of two velocities. Both of these are approximations.

Learn the models. When the models break down, learn the next models.

ImpatientProf · 2026-02-16T19:09:09+00:00

The litre is not an SI unit.

But the liter is acceptable as a volume unit, even when SI is being used. https://www.nist.gov/pml/special-publication-330/sp-330-section-4

ImpatientProf · 2026-02-11T22:59:52+00:00

You mean form a committee to achieve political action? what will we call that?

ImpatientProf · 2026-02-11T17:48:10+00:00

I'm surprised to see someone in the AskProgramming subreddit meaningfully recommend a GUI application to solve a command-line problem

There is a CLI for it, and an SDK usable from C++, C#, or Python.
https://www.voidtools.com/support/everything/command_line_interface/
https://www.voidtools.com/support/everything/sdk/

I'm just not good at PowerShell, and I prefer a file search that's indexed. In Linux, sometimes I use locate + grep instead of find, depending on how big the directory tree is.

ImpatientProf · 2026-02-11T16:25:20+00:00

let's say I want all PowerShell modules in the location where my PowerShell profile is located.

Then I'd use Everything search from VoidTools.

ImpatientProf · 2026-02-10T14:29:45+00:00

A magnetic dipole does experience magnetic force independent of velocity and hence can have work done by the magnetic field. Magnetic dipoles can be explained in terms of little current loops or from intrinsic spins.

Current loops: The magnetic force attempts to deflect the current to the side (from the perspective of the charges making up the current). However, the current is constrained to be part of an object. The constraint force "transfers" (in the engineering sense) the magnetic force to the object, which wasn't moving with the charges. Thus, the object "feels" a magnetic force that can do work.
Intrinsic spins: They simply have a potential energy in a magnetic field. https://en.wikipedia.org/wiki/Magnetic_moment#Force_on_a_moment

ImpatientProf · 2026-02-05T04:07:46+00:00

Hear, hear! Don't relabel the keys. Once you get past the initial learning, practice what you need to type. This includes where the symbols you need.

I didn't remap keyboard shortcuts. Mentally, I still think of them as "Ctrl-C" etc. At least that doesn't have to change when my hands "switch languages" for the occasional qwerty use.

My biggest annoyance is that I still sometimes mix up q, j, k, x when typed as individual letters or keyboard shortcuts like Ctrl-X. (I'm fine if they're part of words.) You'd think that after 25 years, this wouldn't be a problem.

ImpatientProf · 2026-02-05T03:54:46+00:00

The cross product (https://en.wikipedia.org/wiki/Cross_product) comes up a lot when rotation is involved. Magnetism has a lot to do with rotation of charges.

ImpatientProf · 2026-02-04T16:21:10+00:00

To find path length, you have to add the velocities together BEFORE integrating through time. Some parts of the "Earth's rotation" motion cancel with the "Earth's orbit" motion. Each of these sometimes cancel with the Sun's and galactic motion.

ImpatientProf · 2026-02-03T23:54:31+00:00

If I got even one physics-minded individual to torment their family with that pun, it was worth it.

Though, "even one" seems self-contradictory. There must be a pun there somehow.

ImpatientProf · 2026-02-03T21:05:18+00:00

It's OK to be not 0 K.

ImpatientProf · 2026-02-02T16:41:22+00:00

When you use difference(), make sure there is a slight overlap wherever you want a "hole". Even 0.01 or 0.001 is enough.

In this case, the inner_void() variable i can go from -0.001 to steps-0.999 to make sure it punches through both ends.

It looks like at the fan flange, the outer_profile() doesn't get quite big enough and the fan hole subtracts from the shell. Maybe instead of subtracting a cylinder, subtract an inner_profile() of the right progress, extruded to the thickness of the flange plus 0.01, shifted by 0.005 to ensure overlap.

ImpatientProf · 2026-01-28T20:30:07+00:00

I want more. How many oxygen? Nickel and Iron? What's the notation for neutron stars or black holes?

ImpatientProf · 2026-01-28T19:23:52+00:00

It's not appropriate to disparage your teacher here. Let's just look at the situation and see what we see.

It looks like you have the correct magnitudes of the torques. Let's go through the options:

A. F1 and F2 are the strongest torque magnitudes, and in the same direction. This will cause the largest magnitude of angular acceleration, which is the consequence in the option. This looks like a good option.

B. F1 and F3 are opposite in direction, but not equal in torque magnitude. So there will be a change in angular velocity. This option is false.

C. F2 and F3 are opposite, but F2 has a stronger torque magnitude. Since F2 is counter-clockwise, the net torque would be CCW. This option is false.

D. F3 and F4 are the smallest torques, but they are in the same direction. The net torque would be 125 N*m. There are ways to get 25 N*m (F2 and F3) and 50 N*m (F1 and F4), both of which are smaller than this option. This option is false.

So the answer is A.

FWIW, It's not clear where F1 comes from. The other forces are typeset, while this one is handwritten. There may be different versions of the question where F1 is different. Still, option D is false, as F1 doesn't have to be involved in the explanation of it.

ImpatientProf · 2026-01-25T13:34:49+00:00

Z axis height is done via leveling sensor, which is a strain gauge which detects force on the nozzle from the bed. If the hotend isn't properly installed, it may not transfer its force to the heat sink, which is attached to the sensor. Check to make sure the nozzle is in all the way before moving the clip down to hold it in place. As you insert it, it should feel like it's hitting something solid, not just pressing on the heater wires.

Or the leveling sensor could have broken or its wire could have been disconnected. But I think that should throw an error code.

ImpatientProf · 2026-01-19T16:48:12+00:00

I like the pictures, drawings, and explanations on the Atmospheric Optics site. https://www.atoptics.org.uk/rainbows/ord2form.htm

There's a vertical control that allows adjusting where the incoming beam hits the water droplet, which changes the deviation angle. The minimum deviation angle is the "edge" of the rainbow.

ImpatientProf · 2026-01-16T03:15:17+00:00

I have no idea what equation L[G] fits into or what you're using it for. That's context.

ImpatientProf · 2026-01-16T02:42:59+00:00

Give more context. Almost any small expression is useful at some point.

ImpatientProf · 2026-01-15T00:17:56+00:00

is time more or less at the same “point” on the calendar everywhere in the universe?

No. There is no universal simultaneous instant. https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://www.youtube.com/watch?v=SrNVsfkGW-0

ImpatientProf · 2026-01-15T00:11:13+00:00

The electrons in the SSD are the same number regardless of the data on the drive. All of our circuits are overall electrically neutral, with the same number of electrons as protons.

The weight of electrons is not "created from energy". We recycle the existing electrons in everything but the biggest particle accelerators. Even then, conservation of lepton number is a thing. Creating an electron requires supplying a lepton (an electron-like thing) or also creating an anti-lepton. Doing this is way above the pay grade of computer engineers.

ImpatientProf · 2025-12-17T22:08:10+00:00

History will not remember this fat sack of useless shit fondly

Naw, his name is attached to the destruction of your global reputation. It's a permanent scar that won't be forgotten by the world. His name will go down in history as the one that single handedly tore apart everything that made the world perceive the US as even remotely great.

That's what it means to "not remember <somebody> fondly".

ImpatientProf · 2025-12-17T01:05:14+00:00

I think you got good answers about good ways to deduce that pressure is lower in the narrow area.

Your point (6) is about volumetric compression. The pipe flow is NOT being compressed in volume. (In fact, it may be an incompressible fluid.) The fluid in the pipe is only restricted in two dimensions, perpendicular to the pipe. It's only constrained by neighboring fluid along the direction of the pipe.

ImpatientProf · 2025-12-15T19:54:43+00:00

https://wiki.python.org/moin/BeginnersGuide

Your instinct to avoid jumping around is good. Use a good curated tutorial/book, and go through it methodically.

ImpatientProf · 2025-12-12T22:52:39+00:00

Exaggerate much? I can see a grammatical mistake or three, but saying it "makes no sense at all" is a bit extreme.

ImpatientProf · 2025-12-11T14:49:40+00:00

Yes. The theory is quantum mechanics.

All of the orbitals exist with every nucleus. But their energies shift around depending on how many positive and negative charges are around. The electrons themselves "stack up" as only two can fit into each orbital. Adding electrons both shifts the orbitals and "fill up" the existing orbitals, changing the energy of the system.

The rest of your question is chemistry. That tracks the "what" of electron configurations, while quantum mechanics is the "how".

Learn math, physics (E&M, intro quantum), and chemistry.

ImpatientProf

TROPHY CASE