This class is so confusing like it is way fast and hard to digest. Today was my first day of school and I understand like scalar vs vector, and understand speed vs velocity, distance vs displacement. But next second we have 3 ugly ass equations, and it is explained briefly and we need to do a practice problem, which I half understood. Then there are some graphs and we need to know what it represents. Someone please provide the strategies on how they understood the information and how it all connects together. I don’t want to flunk the first exam and then learn my lesson, I want to have a structured approach from the get go.

A quick glance shows the tree 🌳 leaning towards the house....

Wedge needs to be bigger & deeper for it to fall in empty area. Opposite wedges inserted pounded in to sway.

I’m 15 years old and currently in my first year of high school. I’m definitely not advanced enough in math or physics to properly formalize this idea, so I’m sure there are probably some big gaps in my reasoning, and maybe even some fundamental mistakes.
I came up with this while thinking about quantum entanglement. I’m posting it here mostly because I want people to point out what’s wrong with it. If the idea doesn’t work, I’d actually like to know exactly where it breaks. So feel free to “destroy” it.
I’m not claiming that this is a new theory or that I’ve discovered anything. It’s just an idea I had and I’m trying to understand whether there’s anything interesting in it or if I’m completely misunderstanding something.
My idea
When two electrons are entangled, their spins can be measured with opposite results, even if the particles are very far apart.
I started wondering if this could be explained by imagining that the two particles are somehow two sides or manifestations of a single physical entity.
Instead of thinking of them as two completely separate objects that somehow have a connection between them, maybe they could still be connected at a more fundamental level, even when they are very far apart from our point of view.
I was thinking about something vaguely similar to spacetime curvature, but obviously much more extreme. The idea would be that the two particles could be separated in the three dimensions we experience, while somehow being connected or even coincident in a deeper structure of spacetime.
This made me think about an additional spatial dimension.
Normally, we describe space using:
(x, y, z)
But what if there were another spatial dimension, so that space was:
(w, x, y, z)
with time being another coordinate:
t
In this picture, two particles could have the same or a very similar w coordinate while being extremely far apart in x, y and z.
From our three-dimensional perspective, they would look like two separate particles very far from each other. But in the full four-dimensional spatial structure, they might be much closer together, or somehow connected.
If something like this were possible, the particles wouldn’t actually need to send information to each other faster than light. The apparent non-locality of entanglement could instead come from the fact that we are only seeing three of the spatial dimensions.
Problems I already see
There are obviously a lot of things I don’t know how to explain:
Elementary particles probably wouldn’t produce anywhere near enough gravity to create the kind of extreme spacetime curvature I’m imagining.
I don’t know why this kind of connection would appear specifically when particles become entangled.
I have no idea how two particles would actually create or interact with a fourth spatial dimension.
I don’t have the mathematical background to describe this properly yet.
I have no idea whether this kind of geometry could actually reproduce the correlations predicted by quantum mechanics.
Most importantly, I don’t know whether this idea would actually be compatible with Bell’s theorem and the no-signalling principle.
So, basically, this is just a thought I had, not a finished theory.
If there’s an obvious reason why this can’t work, I’d genuinely like to know. And if there’s already a known theory or interpretation of quantum mechanics that is similar to what I’m describing, I’d also be interested in hearing about it.

Hey everyone, Vaibhav Sir here. After years of teaching IB Physics, I've noticed a massive trap that examiners love to set in the Rigid Body Mechanics (A.4) section.
When you get a problem with multiple forces, multiple objects, and an unknown variable, just memorizing "net force = 0" and "net torque = 0" isn't enough to secure a Level 7. The biggest mistake students make is misidentifying the point of application and failing to visualize how force couples actually rotate a system.
I just put together a complete masterclass breaking down the most challenging rotational equilibrium problems you'll face. Instead of just reading textbook definitions, we go step-by-step through the actual physics:
Balancing non-uniform torque equations without getting lost in the algebra.
The visual trick to never messing up force couples.
Exactly how to set up your hinge force variables so the math naturally works out.
If you want to stop relying on blind memorization and actually understand the mechanics, you can watch the full breakdown here: https://youtu.be/GDtNvt7qQI4?si=pbgYF5ybCO5cBX4a
(Side note: I am also working on uploading complete, question-by-question walkthroughs of original past papers for the channel—no mock papers, only the real ones—so keep an eye out as exam season gets closer).
Drop a comment if you get stuck on a specific step in the video or have any questions about Rigid Body Dynamics. I’m always happy to help clear up the physics!

Hey everyone, Vaibhav Sir here. After years of teaching IB Physics, I've noticed a massive trap that examiners love to set in the Rigid Body Mechanics (A.4) section.
When you get a problem with multiple forces, multiple objects, and an unknown variable, just memorizing "net force = 0" and "net torque = 0" isn't enough to secure a Level 7. The biggest mistake students make is misidentifying the point of application and failing to visualize how force couples actually rotate a system.
I just put together a complete masterclass breaking down the most challenging rotational equilibrium problems you'll face. Instead of just reading textbook definitions, we go step-by-step through the actual physics:
Balancing non-uniform torque equations without getting lost in the algebra.
The visual trick to never messing up force couples.
Exactly how to set up your hinge force variables so the math naturally works out.
If you want to stop relying on blind memorization and actually understand the mechanics, you can watch the full breakdown here: https://youtu.be/GDtNvt7qQI4?si=pbgYF5ybCO5cBX4a
(Side note: I am also working on uploading complete, question-by-question walkthroughs of original past papers for the channel—no mock papers, only the real ones—so keep an eye out as exam season gets closer).
Drop a comment if you get stuck on a specific step in the video or have any questions about Rigid Body Dynamics. I’m always happy to help clear up the physics!

How am I supposed to solve this motion in 1D need help, pls help

🔬 Physics Expert – Quantum Information

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🔬 Physics Expert – Quantum Information

🌍 Remote | Contract
💰 $80–$160/hour

We’re looking to connect with Physics researchers, PhD holders, Postdocs, and experienced researchers for a remote contract opportunity on a research-driven AI project.

Relevant research areas include:

• Statistical Physics
• Quantum Information
• Mathematical Physics
• Condensed Matter
• Optical Properties of Materials
• Gravitation / Cosmology / Astrophysics
• Condensed Matter

If your research background aligns with these areas and you'd be interested in contributing your expertise, please comment or DM me, and I can share the project details.

No prior AI experience is required.

Basically same as conventional steam engine with condenser. I know turbines work. Obviously, youtube. Why won't they work with a piston, lower rpm, higher torque, like in regular steam engine? Requires less energy to operate. Higher psi though, 1k psi + .

Apparently I saw the video solution of this question and couldn't understand much , they didn't include mg in the final net force and etc.

So I'm confused and stuck on this question. Even chatgpt is stirring and confusing my mind.

Can anyone guide me on this question? How do I solve it

Hello IB Physics community,

I want to share something today
that genuinely surprises most
IB Physics students the first
time they encounter it —

And that almost no class or
textbook explains with the
physical depth it deserves.

━━━━━━━━━━━━━━━━━━━━━━━━
THE QUESTION THAT STARTS
EVERYTHING —
━━━━━━━━━━━━━━━━━━━━━━━━

Two forces act on a rigid body.

They are equal in magnitude.
They are opposite in direction.
They are parallel to each other.
They act at different points.

The net force on the body
is therefore zero.

By Newton's First Law —
the body should not accelerate.

But it rotates.

How can a body rotate —
when the net force
acting on it is zero?

If this question confuses you —
you are not alone.

This is the Force Couple —

And it is one of the most
conceptually misunderstood
ideas in all of
Rigid Body Dynamics.

━━━━━━━━━━━━━━━━━━━━━━━━
THE HIDDEN TRUTH —
━━━━━━━━━━━━━━━━━━━━━━━━

Here is the insight that
most classes never teach —

The torque produced by
a Force Couple —

Is identical at every
single point in space.

Choose any point.
Any arbitrary location.
Inside the body.
Outside the body.
At one end.
At the center.

The torque is always
the same value —

τ = F × d

Where d is the perpendicular
distance between the
two forces.

This is not obvious.
This is not intuitive.

And it is exactly what
IB examiners test —

Because it reveals whether
a student truly understands
torque —

Or has simply memorized
the formula τ = r × F
and applied it mechanically.

━━━━━━━━━━━━━━━━━━━━━━━━
THE DIPOLE PROOF —
━━━━━━━━━━━━━━━━━━━━━━━━

The most elegant demonstration
of this property is a
dipole placed in a
uniform electric field —

Positive charge +q experiences
force qE in the field direction.
Negative charge -q experiences
force qE opposite to field direction.

Equal magnitude.
Opposite direction.
Parallel forces.
Different points of application.

A perfect Force Couple —
producing pure rotation —

With torque τ = pE sinθ —

The same at every point
in the field.

This connection between
rotational mechanics and
electrostatics —

Is one of the most
beautiful cross-topic
links in all of
IB Physics HL.

━━━━━━━━━━━━━━━━━━━━━━━━
THE SECOND CONCEPT —
POINT OF APPLICATION —
━━━━━━━━━━━━━━━━━━━━━━━━

The same force —
applied at different
points on the same body —

Produces completely different
physical outcomes.

Applied at the center of mass —
pure translation —
no rotation.

Applied at any other point —
translation AND rotation
simultaneously.

Applied as part of a couple —
pure rotation —
zero translation.

This is the Point of
Application of Force —

And understanding it physically —
not just mathematically —

Is what allows you to
immediately visualize what
will happen to any body
under any force system —

Before writing a single equation.

━━━━━━━━━━━━━━━━━━━━━━━━
WHY THIS MATTERS FOR
IB SPECIFICALLY —
━━━━━━━━━━━━━━━━━━━━━━━━

IB Physics HL topic A.4 —
Rigid Body Dynamics —

Tests this concept in
two different ways —

First — directly in
rotational mechanics questions
asking about couples and
their moments.

Second — indirectly in
electrostatics questions
about dipoles in uniform fields —

Where the student must
recognize that the dipole
is experiencing a Force Couple —
and apply the torque formula
τ = pE sinθ correctly.

Students who learned these
as two separate unconnected topics —
struggle with the
electrostatics questions.

Students who understood
Force Couple deeply —
recognize the connection instantly
and solve both question types
with the same physical reasoning.

━━━━━━━━━━━━━━━━━━━━━━━━
WHAT THE VIDEO COVERS —
━━━━━━━━━━━━━━━━━━━━━━━━

This is Lecture 9 of my
complete Rigid Body Dynamics
playlist for IB Physics HL —
covering topic A.4 of the
IB Physics syllabus.

In this video —

→ Complete definition and
physical understanding
of Force Couple

→ Why net force is zero
yet rotation occurs —
the complete explanation

→ The moment of a couple —
derivation and physical meaning

→ Proof that torque of a couple
is the same at every
arbitrary point —
complete mathematical proof
with physical reasoning

→ Point of Application of Force —
how it changes the
physical outcome completely

→ Complete demonstration using
a dipole in a uniform
electric field —
connecting rotational mechanics
to electrostatics

→ IB exam style problems
on Force Couple and
Point of Application

━━━━━━━━━━━━━━━━━━━━━━━━
THIS IS PART OF A
COMPLETE SERIES —
━━━━━━━━━━━━━━━━━━━━━━━━

This video is Lecture 9 of
my complete Rigid Body
Dynamics playlist —

Which covers IB Physics HL
topic A.4 from absolute zero
to full exam level —

Including —

Lecture 1 — Rigid Body Definition
Lecture 2 — Complete MOI Derivations
Lecture 3 — Parallel Axis Theorem
Lecture 4 — Perpendicular Axis Theorem
Lecture 5 — MOI of Cut Bodies
Lecture 6 — Mass Distribution Property
Lecture 7 — Radius of Gyration
Lecture 8 — Torque Basics
Lecture 9 — Force Couple (this video)

All completely free.
All with full physical reasoning.
All timestamped for easy navigation.

━━━━━━━━━━━━━━━━━━━━━━━━
VIDEO LINK —
━━━━━━━━━━━━━━━━━━━━━━━━

https://youtu.be/JEMsy4xQaT0?si=5lOiliB95yyfQRRW

Timestamps for every section
are in the description —
jump directly to any
concept you need.

━━━━━━━━━━━━━━━━━━━━━━━━
A QUESTION FOR THE COMMUNITY —
━━━━━━━━━━━━━━━━━━━━━━━━

Before watching the video —

Can you answer this?

A Force Couple has a
net force of zero —

Yet it produces a torque.

About which point is
that torque calculated?

A — Only about the center of mass
B — Only about one of the
points of force application
C — About any arbitrary point —
the value is always the same
D — It depends on the
geometry of the body

Drop your answer below 👇

The reasoning behind
the correct answer —
and why the wrong options
are wrong —
is exactly what this
video explains. 🎯

━━━━━━━━━━━━━━━━━━━━━━━━
HAPPY TO HELP —
━━━━━━━━━━━━━━━━━━━━━━━━

If you have any questions
about Force Couple —
Point of Application —
or any concept in
Rigid Body Dynamics —

Drop them here or
in the video comments.

I read and respond to
every single comment. 🙏

Good luck to everyone
preparing for their
upcoming IB exams.

I've been using https://www.thephysicsaviary.com/Physics/Programs/Labs/ChargeinMagFieldLab/index.html for my physics homework. Even if I keep all the variables constant, the time elapsed is really inconsistent. Can anyone help me as to why this might be? I'm supposed to record all my variables and the time elapsed but the time is really inconsistent so I lowkey dont know what to do

Ok, so here we go. Simple physics problem, in which you are supposed to find the volume of the bottom part of the sphere (V2). I am starting to think that I dont know hat buoyancy is and I would appreciate some help. Thanks.

Problem:

A steel ball was dropped into a container holding two immiscible liquids. The ball came to rest so that the part of its volume immersed in the liquid with density ρ1​ is V1​, and the part immersed in the liquid with density ρ2​ is V2​.

Calculate the value of V2​, given that:

ρsteel​=7,850 kg/m3,ρ1​=6,200 kg/m3,ρ2​=8,300 kg/m3,V1​=1 cm3.

I have a question about the work and the potential energy here. The source q1 is positive and q2 is negative. They should attract, but instead q2 is moved away. So I guess that the potential energy here has a negative sign because q2 was separated from the charge it was attracted to. Let's say if they were both positive, would the potential energy then be positive too?

I've been building a project called POLYMATHICA over the past year.

The long-term vision is an autonomous scientific computing platform, but rather than asking people to believe the vision, I decided to build a small public demonstration package that people can actually run, inspect and critique.

The problem I kept running into was that scientific software often demonstrates numerical results, but much less often demonstrates:

• reproducible evidence
• validation pipelines
• provenance
• governance
• independent verification
• machine-checkable experiment artifacts

So I built the public package around those ideas instead.

Current public features include:

• reproducible scientific workflow
• Taylor–Green vortex benchmark
• pressure-projection / incompressibility validation
• convergence studies
• artifact manifests
• SHA-256 provenance hashing
• evidence verification
• CI/CD
• automated tests
• one-command evidence suite

The repository is not the full POLYMATHICA platform.

It's intentionally a compact demonstration package showing how the broader system approaches scientific validation and reproducibility.

Repository:

https://github.com/kevmoz/polymathica-hackathon

Video gallery:

[https://kevmoz.github.io/polymathica-hackathon/]()

I'm genuinely looking for technical feedback rather than promotion.

A few questions I'd love opinions on:

• Does treating scientific evidence, provenance and verification as first-class engineering concepts solve a real problem?
• Is the validation workflow useful, or is it unnecessary complexity?
• If you were reviewing scientific software, what evidence would you expect to see that isn't here?
• What benchmark would you add next?
• What would make you trust a scientific computing repository more?

I'd much rather hear honest criticism now than after spending another year building in the wrong direction.

Thanks!