Question

If a person $A$ is moving with velocity $2Km/h$, person $B$ is moving withe velocity $3km/h$ and the angle between the direction of movements of $A$ and $B$ is ${60}^o$, then the velocity of $A$ relative to $B$ in the direction of $A$ is

• A. $\sqrt{13-6\sqrt{3}}$
• B. $\sqrt{13+6\sqrt{3}}$
• C. $\sqrt{7}$
• D. $\sqrt{19}$

Answer 1

The correct option is C $\sqrt{7}$

$\therefore$ Relative velocity $76m/s^2$
$=\sqrt{2^2+3^2-2\times 2\times 3\cos {60}^o}$
$=\sqrt{7}$