Question

A standing man, observes rain falling with velocity of $20m/s$ at an angle of ${30}^{\circ }$ with the vertical. Find the velocity with which the man should, moves so that rain appears to fall vertically to him.

• A. $20m/s$
• B. $16m/s$
• C. $10m/s$
• D. $7m/s$

Answer 1

The correct option is C $10m/s$

Simply question is asking to find the velocity of man with respect to ground
so, on resolving the forces in both horizontal direction we find that,

$V_{r,m}$=$20cos\theta =17.32m/s$

$V_{m,g}$=$20sin\theta =10m/s$

where, $\theta$=${30}^0$

Here in question it is mention that find the velocity with which rain appears to fall vertically to him which is equal to $V_{m,g}=10m/s$