Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    I just can't seem to draw resultant velocity triangles correctly.
    I have just done a question from January 2006 and the mark scheme uses the diagramName:  Capture.PNG
Views: 64
Size:  5.5 KB
    (The question asks to find V).
    I however drew it differently so I still had an included angle but on my diagram that angle was 45.
    I just don't seem to be able to understand how you know where to draw the different velocities.
    Any advice
    Many thanks
    Offline

    22
    ReputationRep:
    (Original post by orange8120)
    I just can't seem to draw resultant velocity triangles correctly.
    Could you provide the question?
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Zacken)
    Could you provide the question?
    Name:  Capture.PNG
Views: 63
Size:  68.4 KB
    Offline

    3
    ReputationRep:
    (Original post by orange8120)
    Name:  Capture.PNG
Views: 63
Size:  68.4 KB
    For 1 (a) (i), try to use trigonometry for right angled triangles. For part 1 (a) (ii), try now to use the fact that this a right angled triangle to work out v.

    For (b), a force diagram is certainly useful. You say in the OP you struggle with this. The way I would approach this would be to literally squash the forces together.

    So place the line for the velocity of the water going into the line representing the velocity of the boat. Then my resultant will be the line connecting these two vectors, so to make a resultant force triangle (see my diagram).

    This triangle is not right angled and so you need to consider how you work out the lengths of the sides of a right angled triangle. The angle between the two sides can be worked out using basic geometry.

    Let me know if you need any further help!
    Attached Images
     
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Would you like to hibernate through the winter months?
    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
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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