**Description**

This programme looks at the mathematical modelling of physical phenomena as a cross product of vectors. It deals with three physically different problems - the deflection of an electron beam in a ...magnetic field, the angular rotation of the earth, and a north seeking gyrocompass.

Module code and title: | MS283, An introduction to calculus |
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Item code: | MS283; 14 |

First transmission date: | 29-08-1979 |

Published: | 1979 |

Rights Statement: | |

Restrictions on use: | |

Duration: | 00:23:56 |

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Producer: | Martin Wright |

Contributors: | Alan Durrant; A. Daniel Lunn |

Publisher: | BBC Open University |

Keyword(s): | Electron beams; Gyrocompass; TV tubes |

Footage description: | Shots of a spinning bicycle wheel suspended by its axle with a rope. Daniel Lunn points out the vectors at work (spin, rotation and torque) which keep the wheel in balance. Alan Durrant demonstrates the deflection of an electron beam by a magnetic force vector, first on a television screen and then by applying a current coil magnet to an electron/gun vacuum tube. Durrant goes on, with a modified form of the experiment set up above, to get a quantitative measure of the electron beam deflection. With the aid of a cut-away model of the Earth, Daniel Lunn explains how the magnitude of the Earth's rotational vector at a particular point on the globe is calculated and goes on to use this method to arrive at an abstracted definition of a cross product. Alan Durrant goes back to the current coil/electron beam apparatus to verify experimentally that this definition of a cross product works for different physical phenomena. Lunn lists two properties which result from the definition for a cross product and which need close attention when doing calculations. These are the formation of a vector cross product with itself and the signs of the vectors in cross product calculations which determine the direction of the product vector. Alan Durrant, writing on a board, calculates the cross product for two vectors expressed in terms of Cartesian units. Lunn sums up the programme so far and then he and Alan Durrant demonstrate the vector cross product principle in a physical situation - a north-seeking gyrocompass. |

Master spool number: | 6HT/73046 |

Production number: | 00525_4304 |

Videofinder number: | 914 |

Available to public: | no |