Question

The resultant of two given vectors is minimum when angle between them is equal to

• A. ${90}^o$
• B. $0^o$
• C. ${180}^o$
• D. ${60}^o$

Answer 1

The correct option is C ${180}^o$

Resultant of two vectors is given by parallelogram law of vector addition. As per this law, the resultant vector is $R=\sqrt{(}{A}^2+B^2+2ABcos\theta )$. Here A and B are the two vectors and $\theta$ is the angle between them. You can see that $R$ will be minimum when $\theta$ is equal to ${180}^o$ that is when the 2 vectors are antiparallel to each other