If $\vec A = 2\hat i + \hat j - \hat k,\,\vec B = \hat i + 2\hat j + 3\hat k$ and $\vec C = 6\hat i - 2j - 6\hat k$ then the angle between $(\vec A + \vec B)$ and $\vec C$ wil be ....... $^o$

If $\vec{a}$ and $\vec{b}$ makes an angle $\cos ^{-1}\left(\frac{5}{9}\right)$ with each other, then $|\vec{a}+\vec{b}|=\sqrt{2}|\vec{a}-\vec{b}|$ for $|\vec{a}|=n|\vec{b}|$ The integer value of $n$ is . . . . . . .. 

Force $F$ applied on a body is written as $F =(\hat{ n } \cdot F ) \hat{ n }+ G$, where $\hat{ n }$ is a unit vector. The vector $G$ is equal to

Let $\vec{A}=2 \hat{i}-3 \hat{j}+4 \hat{k}$ and $\vec{B}=4 \hat{i}+j+2 \hat{k}$ then $|\vec{A} \times \vec{B}|$ is equal to ...................

Vector product of two vectors $2\hat i\, + \,\hat j\,$ and $\hat i\, + \,2\hat j\,$ is