Question

The Janasena Party president Pawan Kalyan has to start its procession in an area in vijayawada where wind is blowing at a speed of $$20km/h$$ along the north-east direction and party flags with the symbols of Hexagram (six pointed star), on the vehicles are fluttering. If the procession starts with a speed of $$14.14km/h$$ towards north, find the direction fluttering of flags on the vehicles.
A. 37 S of W
B. East
C. N-E
D. 53 N of E

Answer 1

Hint: Wind is blowing at a speed of $$20km/h$$ along with North -East direction. Flag is fluttering on the vehicle moving towards the North. Procession starts with speed of $$14.14km/h$$.

Complete step by step answer:
Given :
Wind speed = $$20km/h$$ along with North-East direction.
Procession initial speed = $$14.14km/h$$ towards North
Since wind speed is $$20km/h$$ along with the North-East direction, the flag will also move in the North-East direction when a vehicle is in an idle position.
The graph for given information can be drawn to understand it better.
When the vehicle starts moving towards the north, the flag will start fluttering in the East direction.

Hence, Option B is correct.

Note:Wind is blowing at a speed of $$20km/h$$ along with North -East direction. Flag is fluttering on the vehicle moving towards the North. Procession starts with speed of $$14.14km/h$$. So, in this case we have only 2 options. Flag must be either fluttering in the north east direction or it will change to either north or east.
If it was stationary it would be fluttering in the north east direction but since it was moving in the north direction, the north component of the air is cancelled out and only the east component of the air flow is effective. Hence, the flag was fluttering in the east direction.
Also note that the north component of the movement is exactly equivalent to the north component of the air, which was blowing at the speed of 20.