Given that $P + Q + R = 0$. Which of the following statements is true?

If two forces of equal magnitudes act simultaneously on a body in the east and the north directions,then:

$A$ truck travelling due north at $20 \, m/s$ turns west and travels at the same speed. The change in its velocity is

The resultant of two vectors $\vec{A}$ and $\vec{B}$ is perpendicular to $\vec{A}$ and its magnitude is half that of $\vec{B}$. The angle between vectors $\vec{A}$ and $\vec{B}$ is . . . . . . (in $^{\circ}$)

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

Give the equations to find the magnitude and direction of the resultant vector of two vectors $\vec{A}$ and $\vec{B}$ that are inclined at an angle $\theta$ to each other.