If $|\vec{P}+\vec{Q}|=|\vec{P}|=|\vec{Q}|$,then the angle between $\vec{P}$ and $\vec{Q}$ is: (in $^{\circ}$)

If a particle moves from point $P (2, 3, 5)$ to point $Q (3, 4, 5)$,its displacement vector is:

Two vectors $\vec{A}$ and $\vec{B}$ are parallel to each other if one is a scalar multiple of the other,i.e.,$\vec{A} = k\vec{B}$. Which of the following pairs of vectors are parallel?

The position vectors of points $A, B, C$ and $D$ are $A = 3\hat{i} + 4\hat{j} + 5\hat{k}$,$B = 4\hat{i} + 5\hat{j} + 6\hat{k}$,$C = 7\hat{i} + 9\hat{j} + 3\hat{k}$ and $D = 4\hat{i} + 6\hat{j}$. Then the displacement vectors $\overrightarrow{AB}$ and $\overrightarrow{CD}$ are:

The angles which a vector $\hat{i} + \hat{j} + \sqrt{2} \hat{k}$ makes with $X, Y$ and $Z$ axes respectively are

$A$ physical quantity which has a direction: