Vectors A, B and C satisfy A·B=0 and A·C=0. Which vector is parallel to A?

Question

G1 Physics · Accepted Answer

Step 1: Both B and C lie in a plane perpendicular to A. Step 2: Their cross product B×C is perpendicular to that plane, hence parallel to A (for nonparallel B,C). Final answer: C — B×C.