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B.1. Rigid Bodies and Rotational Dynamics

In Section 6.1 we looked at motion in a circle, but exclusively at objects moving at constant speed round a circle. We understood the idea that even though their speed is constant, they are accelerating because there is a resultant centripetal force acting. Now, we will build upon these ideas to look at objects that are not travelling at a constant speed - i.e. they have an angular acceleration. Most of the stuff we look at has analogues with some of the linear motion stuff we looked at tin the beginning. For example, we have angular suvat equations, we have angular momentum, we have rotational equilibrium and angular equivalents of Newton's laws.

 

Torque

To start off with, we need to make sure we are confident with the various concepts of displacement, velocity and acceleration (and their scalar equivalents). If you need a bit of a recap, flick back to the section on vectors (particularly resolving, addition and subtraction). 

Video Lessons

Resources

IB Physics
Option B Notes (Core)
Isaac Physics
Balancing Moments/ Torques
Torques
Level 3/4 applicable to this section
Mr. G
B.1 Teaching Notes
B.1 Student Notes
Physics and Maths Tutor
Engineering Definitions
Engineering Key Points
Engineering Detailed Notes
Rotational Dynamics Flashcards
A Level Resources - content slightly different

Questions

Dr French's Eclecticon
Statics and Moments
Link to Dr French's Site
Extension: Pre-University Material
Isaac Physics
Moments
Physics and Maths Tutor
Torque and Angular acceleration (AQA 1)
Torque and Angular acceleration MS (AQA 1)
A-Level Qs: overlapping content
 

Moments of Inertia

Video Lessons

Chris Doner
Rolling Inertia
IB Specific
Khan Academy
More on Moments of Inertia
Science Shorts
Rotational Dynamics Overview

Resources

IB Physics
Option B Notes (Core)
Isaac Physics
Moments of Inertia
Level 5/6 beyond IB
Mr. G
B.1 Teaching Notes
B.1 Student Notes
Physics and Maths Tutor
Engineering Definitions
Engineering Key Points
Engineering Detailed Notes
Rotational Dynamics Flashcards
A Level Resources - content slightly different

Questions

Dr French's Eclecticon
Moments of Inertia and Rotational Dynamics
Solutions 1
Solutions 2
Link to Dr French's Site
Extension: Pre-University Material
Physics and Maths Tutor
Moments of Inertia (AQA 1)
Moments of Inertia MS (AQA 1)
A-Level Qs: overlapping content
 

Rotational Equilibrium

Newton's First Law says that if the forces on an object are balanced (i.e. it is in translational equilibrium) then it will move at a constant velocity. The angular equivalent states that if the torques on an object are balanced (i.e. it is in rotational equilibrium) then it will move at a constant angular velocity.

Video Lessons

Chris Doner
Rotational Equilibrium
IB Specific
Science Shorts
Rotational Dynamics Overview

Resources

IB Physics
Option B Notes (Core)
Mr. G
B.1 Teaching Notes
B.1 Student Notes
Physics and Maths Tutor
Engineering Definitions
Engineering Key Points
Engineering Detailed Notes
Rotational Dynamics Flashcards
A Level Resources - content slightly different

Questions

 

Angular Acceleration Equations

There are 5 of these angular SUVAT equations.

Video Lessons

Resources

IB Physics
Option B Notes (Core)
Isaac Physics
Angular Equations of Motion
Summary
Rotational N2L
Rotational Kinetic Energy
Mr. G
B.1 Teaching Notes
B.1 Student Notes
Physics and Maths Tutor
Engineering Definitions
Engineering Key Points
Engineering Detailed Notes
Rotational Dynamics Flashcards
A Level Resources - content slightly different

Questions

 

Conservation of Angular Momentum

As before, there is a rotational analogue to the Conservation of Momentum - the Conservation of Angular Momentum. 

Video Lessons

Resources

IB Physics
Option B Notes (Core)
Isaac Physics
Angular Momentum
Level 5/6 Beyond IB
Mr. G
B.1 Teaching Notes
B.1 Student Notes
Physics and Maths Tutor
Engineering Definitions
Engineering Key Points
Engineering Detailed Notes
Rotational Dynamics Flashcards
A Level Resources - content slightly different

Questions

 

Additional Resources

Once you are completely confident with your SUVAT and have had some practice, we can start looking at motion in two dimensions, projectiles.