### Lecture 21: Torque

**Objectives:**In this lecture, students will learn to

- identify torque as the cause for angular acceleration
- construct the cross product of two vectors
- calculate torque created by a force
- analyze rolling without slipping using rotational dynamics
- apply rotational and linear dynamics to problems involving coupled rotation and translation

**Lecture Notes:**

- Powerpoint: lec21.pptx
- Pdf (recommended for printing): lec21.pdf

**Videos:**

Introduction | Video_1.mp4 | |

Demo: turning a bolt | Video_2.mp4 | with captions |

Cross product | Video_3.mp4 | with captions |

Definition of torque | Video_4.mp4 | with captions |

Torque and angular acceleration | Video_5.mp4 | with captions |

Example 1: Rotating rigid object | Video_6.mp4 | with captions |

Example 2: Rolling without slipping | Video_7.mp4 | with captions |

Example 3: Coupled objects | Video_8.mp4 | with captions |

**Extras:**

Additional example problem | Extra.mp4 |