Question

wind is blowing in the east direction with a speed of 1m/s. A bird wishes to travel from tree A to tree B. Tree B is 84 m away from A in a direction 37° north of east. If the velocity of the bird in still air is 3√2 m/s, what is the time taken by the bird to reach B from A​

Answer 1

Explanation:

Answer should be 2m/sec in the direction of wind i.e north. the given problem requires the cyclist to move such that the relative velocity in the horizontal plane should be zero so that rain drops appears to fall virtically.hence he requires to move with exactly the same velocity as the rain drops in the horizontal plane so that relative velocity in horizontal plane is zero.Now the rain drops are being carried away with the wind and have same velocity as the wind in horizontal direction that is 2m/sec in north direction hence he should move with 2m/sec in north direction

Answer 2

Explanation:

Vb = 5 m/s − speed of the bird;

Vw = 3 m/s − speed of the wind;

Vbw = Vb − Vw = Vb + (−Vw)

Hypotenuse of the right triangle ABC:

|Vb,w| = √Vb

√(Vb² + Vw²) = √(5)² + (3)²

= √34

= 5.8 m/s

Relative velocity of the bird with respect to the wind is 5.8 m/s