Question

Which of the following statement(s) is/are correct?

• A. Displacing a vector parallel to itself leaves the vector unchanged.
• B. Three equal vectors cannot add upto zero.
• C. If $|A+B|\ne |A-B|$ they are perpendicular vectors.
• D. Both (b) and (c)

Answer 1

Answer: (A)

Three equal vectors can add upto zero when each of them is inclined at $120^{\circ }$ with the other.
If $|A+B|=|A-B|$, they are inclined at $90^{\circ }$ as shown below.

In this figure, length of $MN$ is equal to length of $MO$.
So, $|A+B|=|A-B|$.
Thus, the statement given in option (a) is correct, rest are incorrect.