Answer: a is parallel to b.
- A a is perpendicular to b
- B a is parallel to b
- C a = b
- D a = -b
Correct answer: B. a is parallel to b
Explanation: a x b = 0 means sin(theta) = 0, so theta = 0 or 180 degrees. The vectors are parallel (or anti-parallel).
Triangle law of vector addition: placing vector b at the head of vector a, the diagonal from the start to the final head gives the resultant a + b.
Concept context
Vectors, dot product, cross product, and geometric applications