Answer: 0.
- A 1
- B i + j
- C 0
- D -1
Correct answer: C. 0
Explanation: i . j = 0 because i and j are perpendicular unit vectors. For perpendicular vectors, a.b = |a||b|cos90 = 0.
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