Solving Addition of Vectors Problem: Peter G's I.B Physics High Journey

[Peter G.]

So, I started my I.B Course for Physics High and we've took off with a simple subject, addition of vectors. We finished it today but the last question was quite hard. I had a try, asked the teacher but the thing is I can't understand what the problem asks for, or how to approach the problem:

A bird flies at a steady speed of 3 m/s through the air. It is pointing in the direction due north. However, there's a wind blowing from west to east at a speed of 2 m/s. It then asked for the resultant velocity and displacement which I handled with no problem and finished off with: In what direction should the bird point if it is to travel in a northerly direction?

So, firstly: By northerly, should the resultant velocity direction be bearing 0? Like, straight line, north? Or the bird should move towards the north direction?

So, the teacher put the answers up the board so after I had a try I looked. From the answer, I managed to reproduce the diagram obviously and identify the angle but I still don't understand the question itself

Sorry, I don't know how to post up the picture but in case you guys find it helpful:
tap.iop.org/mechanics/statics/file_39599.doc

Last question, both answer and question available.(3)

Thanks in advance,
Peter G.

 

[verty]

I think the problem is the problem. I mean, the problem is a bit confusing. It asks for displacement, but we are only given two velocities. One can get the resultant velocity, which I hope you know how to do, but one can't get a displacement, only a rate of displacement (which is just velocity).

So ignoring the question of displacement, determining the resultant velocity you know how to do. The second part is almost the same. Now the resultant velocity must face north. The bird must fly north and a little west, to counter the effect of the wind. How much west must the bird fly? Just enough, that is the clue. Draw a sketch, put in the magnitudes and use your knowledge of trigonometry to find the answer.

 

[Peter G.]

Ah, ok, so the resultant velocity is towards north. For example (this will be a bit confusing). The counter effect of the wind will be 2ms west. I draw one arrowed line towards my left. I draw a North Line, upwards (my resultant direction) and join a 3ms line from the 2ms line to the North line.

Yeah, to know the displacement we would need to know for how long he flew and multiply by our resultant velocity.

Thanks,
Peter G

 

[verty]

You got it. Then draw an accurate scale diagram to measure the angle or use trigonometry, whichever is easier. The answer would be something like 20 degrees W of N, or whatever.

 

[rwisz]

Dear Peter,

Congratulations on starting your I.B Course for Physics High! Addition of vectors is a fundamental concept in physics and it is great that you are already tackling it. It is common to encounter challenging problems in physics, but with determination and guidance, you will be able to solve them.

To answer your question, the resultant velocity in this problem should be pointing in the northerly direction, which means it should have a bearing of 0 degrees. This means that the bird should be moving towards the north direction. The resultant velocity is the combination of the bird's steady velocity of 3 m/s due north and the wind's velocity of 2 m/s from west to east. The direction of the resultant velocity is important because it determines the bird's overall motion.

In order to find the direction the bird should point in order to travel in a northerly direction, you need to consider the angle between the resultant velocity and the bird's original velocity. In this case, the angle would be 30 degrees, as shown in the diagram provided. This means that the bird should point 30 degrees west of north in order to travel in a northerly direction.

I understand that it may be confusing to understand the question and the concept at first, but with practice and asking for clarification when needed, you will get a better grasp of it. Keep up the good work and don't hesitate to ask your teacher or fellow classmates for help when needed.

Best of luck with your physics journey!

Sincerely,