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Applied Maths help

  • 25-11-2018 4:31pm
    #1
    c_f_p99
    Registered Users, Registered Users 2 Posts: 124 ✭✭


    I'm on Relative Velocity and it's those wind questions that are killing me! grrr. Not the calculating true velocity of wind ones, but the "calculate the direction a plane must travel in order to travel straight ones!". The rivers are grand, but them, they're really annoying! I cannot make sense of the diagrams. Can anyone show me exactly the logic behind them? Help is greatly appreciated.


Comments

  • #2
    MathsNerd78
    Registered Users, Registered Users 2 Posts: 8 ✭MathsNerd78


    Say A is the aeroplane and W is the wind. If I put something in brackets, think of it as a subscript.
    Think of V(AW) as the direction the plane would travel in if there were no wind. V(A) is the direction that the plane must travel. This may be due west for example. V(W) is the velocity of the wind. A lot then depends on the information you are given in the question. If you are told the velocity of the aeroplane in still air then this is V(AW). You'll probably be given the velocity of the wind. Therefore, you just use the relationship V(AW) = V(A) - V(W), in which case V(A) = V(AW)+V(W).


  • #3
    c_f_p99
    Registered Users, Registered Users 2 Posts: 124 ✭✭c_f_p99


    Thank you. Although it's when they ask for the angle of flight (from the horizontal or vertical) when it becomes tricky. I suppose just drawing the straight path (vertical) with the direction of the wind (on the right side for south-west and north west) and vice-versa is how I've taught myself to do it. They are still probably the hardest thing in Relative Velocity, imo.


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