Two men, A and B are moving with same speed in North and East direction respectively. In what direction does A observe B to be going?

Solution:
The velocity of car A and car B are represented by the vectors in the direction as given in the question as shown in the figure.
$$\begin{gathered} The relative of car B w.r.t to car A is given by \\ {v}_{BA}⃗ =v_B⃗-V_A⃗ \end{gathered}$$

$$\begin{gathered} The direction \beta is given by \\ \tan \beta =\frac{v_B}{-v_A}=\frac{v_A}{-v_A}=-1 \\ or \beta ={45}^{\circ } in south east. \end{gathered}$$