In the figure below $A,B,$ and $C$ are screw dislocations with ${}_A={}_B=C=$vec$(k)$ and burger's vectors: $b_A=b_B=b_c=$vec$(k).($see orientation of coordinate system$).$

Calculate the total force $($magnitude and direction$)$ acting on dislocation B resulting fro dislocations A and C$.$

Answer formatted as magnitude $($in units of $G\frac{b}{2})$: direction.

$$ L $S^S$

$\frac{b}{2}L$:$+x$

$\frac{b}{2}L$:$-x$

$\frac{b}{L}$:$+x$

b$/$L:$-$x