$A =2 \hat{ i }+\hat{ j }, B =3 \hat{ j }-\hat{ k }$ and $C =6 \hat{ i }-2 \hat{ k }$ Value of $A -2 B +3 C$ would be

- A
$20 \hat{ i }+5 \hat{ j }+4 \hat{ k }$

- B
$20 \hat{ i }-5 \hat{ j }-4 \hat{ k }$

- C
$4 \hat{ i }+5 \hat{ i }+20 \hat{ k }$

- D
$5 \hat{ i }+4 \hat{ j }+10 \hat{ k }$

The position vector of a moving particle at time $t$ is $r =3 \hat{ i }+4 t \hat{ j }-t \hat{ k }$. Its displacement during the time interval $t=1 s$ to $t=3 s$ is

Figure shows three vectors $p , q$ and $r$, where $C$ is the mid point of $A B$. Then, which of the following relation is correct?

If the angle between two vectors $A$ and $B$ is $120^{\circ}$, its resultant $C$ will be

If $a + b + c =0$ then $a \times b$ is

Two vectors $A$ and $B$ inclined at angle $\theta$ have a resultant $R$ which makes an angle $\phi$ with $A$. If the directions of $A$ and B are interchanged and resultant will have the same