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    I may have forgotten how to do vector over the 2 week break.......

    Particle at (3i-7J) travels 50ms^-1 parallel to (7i-24j)

    calculate velocity
    position vector after 2 seconds
    position vector after t seconds and distance from the origin after 10 seconds

    Zacken help pls i'm going to die from too much homework
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    (Original post by thefatone)
    I may have forgotten how to do vector over the 2 week break.......

    Particle at (3i-7J) travels 50ms^-1 parallel to (7i-24j)

    calculate velocity
    position vector after 2 seconds
    position vector after t seconds and distance from the origin after 10 seconds

    Zacken help pls i'm going to die from too much homework

    What does it mean by parallel to that point?

    Can you post the actual question, like a picture?
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    (Original post by Dinasaurus)
    What does it mean by parallel to that point?
    no clue, all help is useful
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    (Original post by thefatone)
    no clue, all help is useful
    Have you got a picture of the question?
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    (Original post by Dinasaurus)
    What does it mean by parallel to that point?

    Can you post the actual question, like a picture?
    everyone in the class wrote down the question and that's all we were given... no sheet given, he just dictated and we wrote it down :/
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    (Original post by thefatone)
    I may have forgotten how to do vector over the 2 week break.......

    Particle at (3i-7J) travels 50ms^-1 parallel to (7i-24j)

    calculate velocity
    position vector after 2 seconds
    position vector after t seconds and distance from the origin after 10 seconds

    Zacken help pls i'm going to die from too much homework
    The vector  7 \mathbf{i}-24 \mathbf{j} has magnitude 25, but the particle is travelling at 50ms-1 so every second the particle moves a displacement of  14\mathbf{i}-48\mathbf{j} .

    So the particle starts at  3\mathbf{i}-7\mathbf{j} and after t seconds it has moved  14t\mathbf{i}-48t\mathbf{j} so we can represent the path of the particle as
     r=(3+14t)\mathbf{i}-(7+48t)\mathbf{j} , where  t is the time the ball has been travelling in seconds.
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    (Original post by B_9710)
    The vector  7 \mathbf{i}-24 \mathbf{j} has magnitude 25, but the particle is travelling at 50ms-1 so every second the particle moves a displacement of  14\mathbf{i}-48\mathbf{j} .
    so i just double it?
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    (Original post by thefatone)
    so i just double it?
    For the velocity yes. They give you the speed and direction and from that you can always find velocity as I have already shown.
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    (Original post by thefatone)
    so i just double it?
    From all that I can remember at the moment, a vector is parallel to another vector if it is a multiple of it
    Like 4i-6j is parallel to 40i-60j as 40i-60j = 10(4i-6j)
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    (Original post by thefatone)
    ...
    Think of it like this, it moves 50 metres per second in the direction of the unit vector \frac{1}{|7i - 24j|} (7i - 24j) so its velocity is \frac{50}{25}(7i - 24j) and hence its position can be written the way B_9710 wrote it.
 
 
 
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