Simply Physics — Torque & Rotational Dynamics
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Introduction

This unit extends Newtonian mechanics to rotational motion, focusing on how objects rotate and what causes changes in their rotational state. It mirrors linear dynamics but uses angular quantities like torque, angular acceleration, and moment of inertia.

Torque: A twisting force, calculated as τ = r·F·sin(θ).
Example: Torque applied to a disk: τ = (radius)(Force from hand)(sinθ).

Moment of Inertia: Measures how mass is distributed relative to the rotation axis, resisting changes in rotational motion.
Sphere: I = (2/5)·m·r²

Torque Equations:
τ = r·F·sin(θ)
τ = I·α, where α is angular acceleration

Relationship of Angular & Linear:
v = ω·r — Linear velocity from angular velocity and radius.

Torque Diagram
Rotational Dynamics Example
Moment of Inertia Illustration

Summary of Key Equations

1. τ = r·F·sin(θ)   (Torque)
2. I = (2/5)·m·r²   (Moment of Inertia for Sphere)
3. τ = I·α   (Torque Equation)
4. v = ω·r   (Linear-Angular Relationship)

Other Resources