Question

1. Rain is falling vertically with the speed of 20m/s, wind starts blowing after some
time with a speed of 20m/s in East to West direction. In which direction should a
boy waiting in a bus stop hold his umbrella? ( give answer with figure )

Answer 1

Answer:

He should hold the umbrella in the east direction.

hope u understand

Answer 2

Given :

• Speed of rain ${\sf (v_r)=20\: m/s}$
• Speed of wind from east to west ${\sf (v_w)=20 \: m/s}$

To Find :

• Direction should a boy waiting in a bus stop hold his umbrella

Solution :

Rain main problem -

If rain is falling vertically with a velocity ${\sf v_r}$ and wind Velocity is ${\sf v_w}$

then velocity of rain relatives to observer will be ${\sf v_{rw}}$

The direction of ${\sf v_{rw}}$ is such that it make an angle ∅ with vertical given by -

$\implies{\sf \theta = tan^{-1}\left(\dfrac{v_w}{v_r}\right) }$

$\implies{\sf tan \theta = \dfrac{20}{20} }$

$\implies{\sf tan \theta = 1}$

$\implies{\bf tan45°=1}$

Answer :

Direction of umbrella should be angle 45° with vertical