Physics - Inertia

Here:
http://www.euclideanspace.com/physics/dynamics/inertia/index.htm

You are discussing the inertia tensor. You have these lines about halfway down
the page:

T = F x s (force times distance, x is the cross product)

substuting F=m a gives,

T = m * s x a

therefore defining h = m * s gives

T = h x a

Here:

T = F x s

is incorrect. The correct equation is T = R X F where R is the distance vector.
This would make the rest of your derivation correct. Starting with T = F X
s and then ending with T = m*s X a would imply that the cross product is communitive,
which it is not.

I have enjoyed the site so far, Thanks

Israel

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see also:

Correspondence about this page

Book Shop - Further reading.

Where I can, I have put links to Amazon for books that are relevant to the subject, click on the appropriate country flag to get more details of the book or to buy it from them.

Game Physics - This book has some useful stuff, its more of a textbook, not a step by step guide (although it does have a disc with a lot of C++ code). About the first third of the book is a physics textbook with theoretical exercises, the middle bit covers physics engine topics, and the last third of the book covers mathematical topics. I think I would use this book as a reference book to lookup the theory behind something I might be working on rather than a book to work through in order.

Robot Dynamics Algorithms (Kluwer International Series in Engineering and Computer Science, 22)

Commercial Software Shop

Where I can, I have put links to Amazon for commercial software, not directly related to the software project, but related to the subject being discussed, click on the appropriate country flag to get more details of the software or to buy it from them.

Mathmatica

Can you help?

Please send me any improvements to here. I would appreciate ideas to make the pages more useful including error correction, ideas for new pages, improvements to wording. It helps if you quote the full URL of the page.

progam

I am working on a project which uses these principles, if you would like to help me with this you are welcome to join in, here:

http://sourceforge.net/projects/mjbworld/

This site may have errors. Don't use for critical systems.

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see also:	numerical approach to collisions Rotations Angular momentum Conservation of angular momentum about centre of mass of whole system
Correspondence about this page	michael Israel
Book Shop - Further reading. Where I can, I have put links to Amazon for books that are relevant to the subject, click on the appropriate country flag to get more details of the book or to buy it from them.	Game Physics - This book has some useful stuff, its more of a textbook, not a step by step guide (although it does have a disc with a lot of C++ code). About the first third of the book is a physics textbook with theoretical exercises, the middle bit covers physics engine topics, and the last third of the book covers mathematical topics. I think I would use this book as a reference book to lookup the theory behind something I might be working on rather than a book to work through in order. Robot Dynamics Algorithms (Kluwer International Series in Engineering and Computer Science, 22)
Commercial Software Shop Where I can, I have put links to Amazon for commercial software, not directly related to the software project, but related to the subject being discussed, click on the appropriate country flag to get more details of the software or to buy it from them.	Mathmatica
Can you help? Please send me any improvements to here. I would appreciate ideas to make the pages more useful including error correction, ideas for new pages, improvements to wording. It helps if you quote the full URL of the page.
progam I am working on a project which uses these principles, if you would like to help me with this you are welcome to join in, here:	http://sourceforge.net/projects/mjbworld/