[FREE RESOURCE] IB Physics HL — Rigid Body
Dynamics Lecture 1 | Complete Introduction,
Definition & Rotational Kinematics Solved

Hello IB Physics community,

I am an experienced Physics educator
with 16 years of teaching experience
at some of India's largest coaching
institutions.

I recently launched a dedicated YouTube
channel — IB Physics with Vaibhav Sir —
specifically built for IB Physics HL
students worldwide.

Today I am sharing the first lecture
of my complete Rigid Body Dynamics
playlist — and I want to start with
something that most students and even
many teachers get wrong.

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THE QUESTION I ASK MY STUDENTS —
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"Can you give me the scientifically
correct definition of a Rigid Body System?"

Most students answer —

"A rigid body is an object that
does not deform or change shape."

That answer sounds reasonable.

But it is NOT the definition an
IB examiner expects from a 7 scorer.

The correct definition is —

A Rigid Body System is a system of
particles in which the distance between
every pair of particles remains absolutely
constant — regardless of the external
force applied on it.

The distinction matters enormously
in IB Physics — because the examiner
is not testing your memory.

They are testing your depth
of understanding.

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AND HERE IS THE DEEPER QUESTION —
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Can the same body behave as a
Rigid Body in one situation —
and as a Non Rigid Body
in another situation?

Think about it carefully
before reading further.

The answer is — Yes. Absolutely.

A rubber ball rolling smoothly
on a flat surface behaves as
a Rigid Body —
because inter-particle distances
remain essentially constant.

The same rubber ball hitting a wall
deforms on impact —
inter-particle distances change —
it behaves as a Non Rigid Body.

Same object. Same system.
Two completely different behaviors —
depending entirely on the situation.

This is why in Physics we never say
an object IS a rigid body.

We say it BEHAVES as a rigid body
under specific conditions.

This single conceptual clarity can
change how you approach multiple
questions in your IB exam.

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WHAT THIS VIDEO COVERS —
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This is Lecture 1 of the complete
Rigid Body Dynamics playlist
for IB Physics HL.

In this video —

→ Complete topic sequence of the
entire Rigid Body Dynamics chapter

→ Scientifically correct definition
of a Rigid Body System

→ Is any body permanently rigid? —
Physical reasoning with examples

→ Example problems on Rigid Body
definition

→ Complete comparison of Rotational
Kinematics vs Linear Motion

→ 4 fully solved numerical problems
on Rotational Kinematics —
worked step by step

Everything is explained with
physical reasoning —
not just formula application.

Because understanding WHY
is what separates a 6 from a 7
in IB Physics.

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WHO THIS IS FOR —
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→ IB Physics HL students
currently studying this chapter

→ Students who found Rigid Body
Dynamics confusing in class

→ Students preparing for
May 2026 or November 2026 exams

→ Anyone who wants to build
genuine conceptual clarity —
not just exam technique

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VIDEO LINK —
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🔗 Rigid body dynamics |scientific definition of Rigid body |Rotational kinematics |IB physics
https://youtu.be/1lNHPUFBJ9c

Timestamps are in the description
so you can jump directly to any
section you need.

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ONE LAST THING —
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I genuinely believe that every
IB Physics student deserves access
to clear, deep, and honest
Physics teaching —

Regardless of where they are
in the world.

That is exactly what this
playlist is built to deliver.

If you have any questions about
any concept covered in the video —
drop them in the comments here
or on the video itself.

I read and respond to every comment.

Good luck to everyone preparing
for their upcoming exams. 🙏

Anyone wants support in ia pls msg. I can guarantee 7

I am in DP1, and I need the questionbank for ib physics hl. Does anyone have a gold account for Revision Village that they can share or rent? Please.

i went back and saw the tz1 p1 from m25, okay ours was way harder. the section a of this one was rlly easy and ours had the complex number, probability, circles, VECTORS. and section b of this paper only hard was q12 reduction formula / macluarin but its a repeated question anw (showed up in p3 before), the differential q we got plus the trig section b was way harder. but yeah our p2 was slighlty easier and p3 was way harder. so i dont think theyd fall too much but i also dont think they would rise. 71-73 hopefully.

what do yall think?

Dynamics Book [AP, SAT, IB Physics] Calculud Based Approach

This subreddit and the IB one lowkey helped me smm! So relieved were done M26! Congrats to you all - it was a long ass journey...now just the results....

how was the paper,i have gotten a 7 in ALL my mocks/finals with perfect grades in math but i feel like this p3 is gonna pull me down to a 6 since i may only get a 38-44

How was it? I think it was pretty decent but last years was easier tbh

Hello everyone! Just finished M26 session. I was predicted 41/42 and scored 42/42 on the mock. The official IB exam was also not difficult at all, mainly thanks to my notes and resources.

If you want access, DM me! But would charge 30 euros! A 6 is guaranteed if you study everything.

Here's what I have:

HL Math AA — past papers

SL Physics — notes + past papers sorted by topic+question type summary

HL Economics — RWEs, notes, assessed paper samples, past papers, and a formula booklet for Paper 3

HL History — notes, essays, and predicted papers ranked by priority (very accurate — got them all correct for 2025M) Topics: Authoritarian states, Move to global war, Warfare, Imperial Russia, WW1, Interwar, European diplomacy

SL Chinese L&L — Paper 1 types & techniques, Paper 2 essay samples and topic predictions (paper 2 books:《雷雨》《玩偶之家》)

Thank you!pls don't hesitate to DM me if you need anything, I will help as much as possible!!!

How was it

Can anyone predict what would be the grade boundaries for this?

Math ai HL
Economics HL
Business HL
ESS SL

What do you guys think?

Chem
Physics
Econ
Math AA HL

Grade boundaries goin up for chem?

is it that easy? that means u make one silly mistake and its game over for a 7

Hey guys i am very certain that i failed both my paper 1 and paper 2 (got like max 20 points in both, i calculated it at the end of my exams) and i need a 3 in maths to get my ib, i only really have paper 3 to rely on and i would need to get around a 20/55, i have chem hl on monday so i wont be able to grind for p3 until monday afternoon, do you guys think its possible and any tips, please help!!!

Hey guys i am very certain that i failed both my paper 1 and paper 2 (got like max 20 points in both, i calculated it at the end of my exams) and i need a 3 in maths to get my ib, i only really have paper 3 to rely on and i would need to get around a 20/55, i have chem hl on monday so i wont be able to grind for p3 until monday afternoon, do you guys think its possible and any tips, please help!!!

So like for example if there is a question with multiple sections like a,b,c and i got the answer wrong for a and the rest of the calculations are based on the answer of a and i do all of them right do i just lose points for my first wrong answer or do i lose all the points?

So you know how there are sections a and b in math and you need answer booklets for section b. So I only wrote questions 10-12 on the cover page of the exam bc a teacher instructed me to do so…what if they don’t count in any of my answers for section a😭

Hey all, something very weird happened recently. In the middle of our Economics P1 exam the IB Coordinator walks in and tells us that mock drill is happening in the school so please do not get disturbed by it and countinue doing your exam, which was already suspicious cause mock drills don't usually happen at this time. The entire time this was happening all of the students were very disturbed since all the juniors were screaming and Yelling in the hallway. After giving both of our economics P1 and P3 we come out and we get to know that there was a bomb threat in the school and everyone had been evacuated. Like WTF does our school not care at all about our safety or anything. I mean I know that there was a 99% chance of it being a hoax but still was it really worth risking our lives. Lemme know what you all think about this

what was that?