Answer: 2sqrt(14).
- A sqrt(14)
- B 2sqrt(14)
- C 4sqrt(14)
- D 14
Correct answer: B. 2sqrt(14)
Explanation: |a| = sqrt(9+4+1) = sqrt(14). |2a| = 2|a| = 2sqrt(14).
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