Relative velocity help -- A bird flying in a wind trying to get to its nest

[Jas]

Homework Statement

A bird can fly in still air at 100km/h. The wind blows at 90km/h from W(x degrees)S. The bird wishes to return to its nest which is due E of its present position. In which direction, relative to the air, should it fly?My textbook says that the velocity of the bird relative to the air (bVa)= 100km/h. But this is in still air,whereas the wind is actually moving at 90km/h. So how is 100km/h= bVa?

Homework Equations

The Attempt at a Solution

 

[berkeman]

Homework Statement

A bird can fly in still air at 100km/h. The wind blows at 90km/h from W(x degrees)S. The bird wishes to return to its nest which is due E of its present position. In which direction, relative to the air, should it fly?My textbook says that the velocity of the bird relative to the air (bVa)= 100km/h. But this is in still air,whereas the wind is actually moving at 90km/h. So how is 100km/h= bVa?

Homework Equations

The Attempt at a Solution

Please draw a diagram with the bird's velocity vector, the wind vector, and the position of the bird's nest. That will allow you to figure out what direction to aim the bird to fly to the nest. You can use the UPLOAD button in the lower right of the edit window to upload your PDF or JPEG drawing.

 

[kuruman]

I am compelled to note as an aside that we have here a pretty fast moving bird flying out of its nest in particularly inclement weather. According to the Saffir-Simpson scale, a tropical storm (one step below a category 1 hurricane) has sustained winds of 63-118 km/h. This problem gives new meaning to the word birdbrain.