Question

A man sitting in a bus travelling in a direction from west to east with a speed of 40km\h observes that the rain – drops are falling vertically down. To the other man standing on ground the rain will appear
A. to fall vertically down
B. To fall at an angle going from west to east
C. To fall at an angle going from east to west
D. the information given is insufficient to decide the direction of rain.

Answer 1

Hint: In this question we are given a man who is sitting in a bus and travelling from west to east and the raindrops are falling. We have to find how the rain appears for another man. To find out , we find out the velocity of rain w.r.t man . After that we find out how the rain appears for another man.

Complete step by step solution:
Given is a man sitting in a bus travelling in a direction from west to east and the raindrops are falling vertically down.


We have to find that how the rain appears for the another man
For this Let ${{v}_{m}}$= velocity of man = -40 km\h
${{v}_{r}}$= actual velocity of rain which is falling at an angle $\theta $ with the vertical
${{v}_{rm}}$= velocity of rain with respect to the moving man ${{v}_{rm}}$
${{v}_{rm}}$= ${{v}_{r}}-{{v}_{m}}$
$\therefore {{v}_{r}}$= ${{v}_{rm}}$+ ${{v}_{m}}$
If another man observes the actual rain then he will find that actually the rain is falling with velocity ${{v}_{r}}$ at an angle going from west to east.

Hence, option B is the correct answer.

Note: In this question, we are given the east, west and vertical direction and we are not talking about north- south direction, so we suppose that all the motions are going on only in this plane.