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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

#### 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

 Chris Doner Torque IB Specific Khan Academy Introdution to Torque Torque of Angled Forces Physics Online Principle of Moments Couples Science Shorts Rotational Dynamics Overview

## 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
Moment 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

#### 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

 Dr French's Eclecticon Moments of Inertia and Rotational Dynamics Solutions 1 Solutions 2 Link to Dr French's Site Extension: Pre-University Material
Angular Acceleration

#### Angular Acceleration Equations

There are 5 of these angular SUVAT equations.

## Video Lessons

 Chris Doner Rotational Kinematics Rotational Dynamics Rolling IB Specific Khan Academy Angular Motion Variables Rotational N2L Science Shorts Rotational Dynamics Overview

## 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

 Dr French's Eclecticon Non Uniform Circular Motion Non Uniform Circular Motion Solutions Link to Dr French's Site Extension: Pre-University Material Physics and Maths Tutor Angular motion (AQA 1) Angular motion MS (AQA 1) Rotational Motion (AQA 1) Rotational Motion MS (AQA 1) A-Level Qs: overlapping content
Angular Momentum

#### Conservation of Angular Momentum

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

## Video Lessons

 Chris Doner Angular Momentum IB Specific Khan Academy Angular Momentum Rotational KE Rolling Problems Science Shorts Rotational Dynamics Overview

## 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

 Physics and Maths Tutor Rotational KE (AQA 1) Rotational KE MS (AQA 1) Angular Work & Power (AQA 1) Angular Work & Power MS (AQA 1) A-Level Qs: overlapping content