Question

Rain is falling vertically downwards with a speed of $4km{h}^{-1}$. A girl moves on a straight road with a velocity of $3km{h}^{-1}$. The apparent velocity of rain with respect to the girl is

• A. $3km{h}^{-1}$
• B. $4km{h}^{-1}$
• C. $5km{h}^{-1}$
• D. $7km{h}^{-1}$

Answer 1

Answer: (C)

$5km{h}^{-1}$

It is given that,

Speed of rain, $v_r=4km/h$

Speed of girl, $v_g=3km/h$

Let v is the apparent velocity of rain respect to the girl. It can be calculated as :

$v=\sqrt{v_r^2+v_g^2}$

$v=\sqrt{4^2+3^2}$

$v=5km/h$

So, the apparent velocity of rain respect to the girl is $5m/s$. Hence, this is the required solution.