question_answer

If the magnitudes of vectors A, B and C are 12, 5 and 13 units respectively and A + B = C, the angle between vectors A and B is:

A) 0                     

B)        \[\pi \]   

C) \[\frac{\pi }{2}\]                        

D)        \[\frac{\pi }{4}\] 

Correct Answer: C

Solution :

[c] \[{{13}^{2}}={{12}^{2}}+{{5}^{2}}+2\times 12\times 5\cos \theta \] \[\therefore \theta =90{}^\circ \]