Of the three methods which have been described, the first two are generally the most suitable for determining the moment or the magnetization of a permanent magnet, and the last for studying the changes which occur in the magnetization of a long rod or wire wl?E:n subjected to various external magnetic forces, or, in other words, for determining the relation of I to H.
Hence the formula is more useful in the form w = (w i +w2)1 2 / (Kd -1 2) = (wl +w 2)lr/ (K -lr) where k= (wl+w2-1-w3)lr/w3 is to be deduced from the data of some bridge previously designed with the same working stresses.
A / / is wl; the reactions at abutments, R I = R2 = 2w/.
Remembering that in this case the centre bending moment Ewl will be equal to wL 2 /8, we see that the horizontal tension H at the vertex for a span L (the points of support being at equal heights) is given by the expression 1..
In ordinary texts some survive, especially as objects of verbs, namely, wL, tw, tn, 1w, at.