Question
The angle between the vectors $(\hat i + \hat j)$ and $(\hat j + \hat k)$ is ....... $^o$
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Answer
(c) $(\hat i + \hat j).(\hat j + \hat k) = 0 + 0 + 1 + 0 = 1$
$\cos \theta = \frac{{\vec A.\vec B}}{{|\vec A||\vec B|}} = \frac{1}{{\sqrt 2 \times \sqrt 2 }} = \frac{1}{2}$
$\theta = 60^\circ $
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