Hey there! Sign in to join this conversationNew here? Join for free
Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    A bird is capable of flying at 80Km/h . It wishes to fly to its nest which is due east of its present position. There is a wind blowing from the north-west at 70Km/h. Find the direction in which the bird must fly to reach its nest.
    Offline

    0
    ReputationRep:
    Draw a diagram.

    You want to draw the birds resultant velocity vector and you want this to be going directly East. However, no matter which way the bird flies, he will be pushed South-East at 70km/h and since it doesn't matter in which order you add vectors to get the resultant, let's start by drawing on this 70km/h vector. Now the problem is saying...at what angle do I draw on the 80km/h vector such that the resultant is horizontal. Provided you know how to add two vectors it shouldn't be difficult.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Spenceman_)
    Draw a diagram.

    You want to draw the birds resultant velocity vector and you want this to be going directly East. However, no matter which way the bird flies, he will be pushed South-East at 70km/h and since it doesn't matter in which order you add vectors to get the resultant, let's start by drawing on this 70km/h vector. Now the problem is saying...at what angle do I draw on the 80km/h vector such that the resultant is horizontal. Provided you know how to add two vectors it shouldn't be difficult.
    Yeh, i mean i tried that, but i get the wrong anwser....??
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hmmm,

    It seems that i have my diagram wrong. Is it possible if you can draw a quick diagram? I mean, i cant seem to draw it???
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Widowmaker)
    |Vw| = 70
    |Vb| = 80
    ehrr....I just had a quick look again and i dont quite agree with the diagram. Shouldnt the velocity of the bird be towards east, and not the velocity of the bird relative to wind??

    Because if this diagram is correct, then i dont understand why it is.
    Offline

    16
    ReputationRep:
    Apologise for the slight error. Misread the question.

    Right. I've re-done the diagram.

    |bVw| = 80
    |Vw| = 70

    => 80/sin45 = 70/sin([email protected]) = 70/[email protected]
    => [email protected] = 70sin45
    => [email protected] = 70sin45/80
    => @ = 52 degrees
    Attached Images
     
    • Thread Starter
    Offline

    0
    ReputationRep:
    ahh!

    Now it makes sence. Thanks.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 26, 2006
Poll
“Yanny” or “Laurel”
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.