PSE Example 8.6 via Reduce

*To*: mathgroup at smc.vnet.net*Subject*: [mg112677] PSE Example 8.6 via Reduce*From*: Eduardo Cavazos <wayo.cavazos at gmail.com>*Date*: Sun, 26 Sep 2010 02:44:00 -0400 (EDT)

Hello, Here's example 8.6 from PSE [1]: http://i.imgur.com/HJLqs.png Here I'll be working with the "exercise" portion of the example; i.e. the case where there is friction between point A and point B. Use Reduce on the set of equations which describe the system between point A and point B: http://i.imgur.com/PLWza.png The result shows that vB is about 12.9. Now use Reduce on the set of equations which describe the system between point B and point C. Also, plug in our value of 'vB' manually: http://i.imgur.com/rujUz.png We get the correct answer for dBC; i.e. about 40.3. Above I solved the problem in "piecemeal" fashion; first I used Reduce on the system from A to B and used the result from that to work with the system from B to C, also using Reduce. I don't have alot of experience with Reduce, but it seems like, in theory, I should be able to throw the whole set of equations at Reduce in one step, instead of in two steps. However, when I try to do so, Mathematica seems to have trouble with it (at least on this system; Pentium M with about 1.5GB RAM). So something along the lines of: http://i.imgur.com/2swfE.png So my questions are... Is this too much for Reduce to handle? Would you recommend the piecemeal method instead? If you have suggestions for a way to better apply Mathematica to the problem at hand, those are welcome also. :-) Thanks! Ed 1: Physics for Scientists and Engineers by Raymond A. Serway and John W. Jewett