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    What does the question mean when it says B relative to A? what do i have to do?
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    (Original post by thefatone)
    What does the question mean when it says B relative to A? what do i have to do?
    Please post the full question.
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    I other words If the question says what is the velocity of a relative to b (or v.v) or what is the bearing of b relative to a (or v.v) it is very different if it says "is b a relative to a"
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    (Original post by thefatone)
    What does the question mean when it says B relative to A? what do i have to do?
    Get the difference between the two position vectors. It is just asking you for the distance between the two vectors. Which is the difference between the two
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    (Original post by notnek)
    Please post the full question.
    (Original post by nerak99)
    I other words If the question says what is the velocity of a relative to b (or v.v) or what is the bearing of b relative to a (or v.v) it is very different if it says "is b a relative to a"
    (Original post by Funnycatvideos)
    Get the difference between the two position vectors. It is just asking you for the distance between the two vectors. Which is the difference between the two
    At 8 am 2 ships A and B are at (\mathbf{i}+3\mathbf{j})km and (5\mathbf{i}-2\mathbf{j})respectively, from a fixed point P
    Their velocities (A)(2\mathbf{i}-\mathbf{j}) and (B) (-\mathbf{i}+4\mathbf{j})

    Show that t hours after 8 am the position vector of B relative to A is given by ((4-3t)\mathbf{i} +(-5+5t)\mathbf{j})
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    (Original post by thefatone)
    At 8 am 2 ships A and B are at (\mathbf{i}+3\mathbf{j})km and (5\mathbf{i}-2\mathbf{j})respectively, from a fixed point P
    Their velocities (A)(2\mathbf{i}-\mathbf{j}) and (B) (-\mathbf{i}+4\mathbf{j})

    Show that t hours after 8 am the position vector of B relative to A is given by ((4-3t)\mathbf{i} +(-5+5t)\mathbf{j})
    fine the position vector of A, then of B, then subtract them and that's B relative to A.
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    (Original post by thefatone)
    At 8 am 2 ships A and B are at (\mathbf{i}+3\mathbf{j})km and (5\mathbf{i}-2\mathbf{j})respectively, from a fixed point P
    Their velocities (A)(2\mathbf{i}-\mathbf{j}) and (B) (-\mathbf{i}+4\mathbf{j})

    Show that t hours after 8 am the position vector of B relative to A is given by ((4-3t)\mathbf{i} +(-5+5t)\mathbf{j})
    The position vector of B relative to A is the vector that goes from A to B i.e. \overrightarrow{AB}.

    And \overrightarrow{AB} = \overrightarrow{OB} - \overrightarrow{OA}
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    (Original post by Zacken)
    fine the position vector of A, then of B, then subtract them and that's B relative to A.
    (Original post by notnek)
    The position vector of B relative to A is the vector that goes from A to B i.e. \overrightarrow{AB}.

    And \overrightarrow{AB} = \overrightarrow{OB} - \overrightarrow{OA}
    Ah this brings back memories.. thanks all
 
 
 
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