Problem 3.251

Find the magnitude and direction of a force vector acting on a unit length of a thin wire, carrying a current $I=8.0 \mathrm{~A}$, at a point $O,$ if the wire is bent as shown in (a) Fig. 3.68a, with curvature radius $R=10 \mathrm{~cm}$ (b) Fig. $3.68 b,$ the distance between the long parallel segments of the wire being equal to $l=20$ cm.