Forces and other tedious stuff

I am a bit concerned over the attitude of the kiwi guy interviewed on CloseUp tonight, as he prepares to defend his home in Cairns against Yasi in a house 4 metres above sea-level when a 5 metre storm surge is predicted. You do the maths. Let’s pray that destruction is just limited to things that can be rebuilt.

On more physicsy matters, this coming semester I’m teaching a paper on Dynamics, for the first time, to cover for a  Mechanical Engineering lecturer who is unable to teach it this year.  It’s a pretty turgid subject, really – all about working out how things move when various forces are applied. It brings in concepts such as torque and angular momentum, centre of mass, centre of rotation, internal constraint forces and other unexciting stuff.

Now, my colleague has kindly furnished me with the text book he uses. Ideally this should help, but after going through it I’m of the opinion that all it does is emphasize how tedious the subject is. Next week I shall be digging in our (refurbished and very flash-looking) library for Feynman’s lectures on physics and having a look at how he deals with it. If Feynman couldn’t make it at least a little interesting, there really is no hope.

However, the major gripe I have with the textbook is that it reduces the subject to a series of unrealistic, oversimplistic, stereotypical problems. These problems suggest that it is all about picking the right formulae and doing maths. Real physics seems conspicuous by its absence. Where are the real engineering problems, like the Karapiro grandstand problem? (I really hope that the engineers who designed the grandstand did know a bit about forces).  I refuse to teach that physics (or, indeed, mechanical engineering)  is about sticking numbers into formulae, which, probably means I’m going to have to ditch that textbook and get something else in place (by the end of this month).

Anyway, I’ll keep you posted how this goes as the semester unfolds. And whether I want to teach the paper again once semester is over.



One thought on “Forces and other tedious stuff”

  • I think you will find Feynman’s approach to elementary mechanics quite different from that found in most textbooks. Most textbooks start with dynamics and Newton’s laws. After a 3-chapter general introduction to Physics and its relation to other Sciences, Feynman begins in earnest with Conservation of Energy and doesn’t get around to Newton until chapter 9!
    In any case, I appreciate the spirit in which this blog entry is written, hope that the Feynman Lectures will help, and wish you the best of luck!
    BTW, here are a couple more books you might want to look at:
    For physics exercises, to accompany FLP, I know of no finer collection (not including the one I am working on now 🙂 than “Introduction to Classical Mechanics with Problems and Solutions” by David Morin (Cambridge Univ. Press, 2007). See: .
    The other is a small book that is available free, lots of fun to read, and has an enormous amount of useful information for the working physicist or engineer:
    “Street-Fighting Mathematics, The Art of Educated Guessing and Opportunistic Problem Solving,” 2010, by Sanjoy Mahajan
    Available free here:
    Best regards,
    Mike Gottlieb
    Editor, The Feynman Lectures on Physics

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