Two particles start simultaneously from the same point and move along two straight lines, one with uniform velocity $\overrightarrow{\mathrm{u}}$ and the other from rest with uniform acceleration $\overrightarrow{\mathrm{f}}$. Let $\alpha$ be the angle between their directions of motion. The relative velocity of the second particle w.r.t. the first is least after a time.

• Correct answer
  A

  $\frac{u \cos \alpha}{f}$
• B

  $\frac{u \sin \alpha}{f}$
• C

  $\frac{\mathrm{f} \cos \alpha}{\mathrm{u}}$
• D

  u $\sin \alpha$.

Hence, the correct answer is option: 'A'.