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    Can anyone do this momentum/impulse question?

    The mark scheme shows:

    33/5mu = 2m(-v--4u)

    I don't get how they've got both the 4u and the v as negative since the question States P is moving due east?

    I can't make sense of it


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    (Original post by KloppOClock)
    when its parallel to i, the sum of the J components will be 0.

    look at how you work out its current position r=r0+vt

    then set the J component of the right hand side of that equation to 0, solve for t
    I dont understand what you do sorry. What do you o with the v
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    Can anyone help me with this question on vectors
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    (Original post by Not_a_horse)
    https://drive.google.com/file/d/0B1Z...w?pref=2&pli=1
    Question 3, if I find W first then use it to calculate R, will I still get full marks, because the mark scheme says not.
    Zacken
    Is this true? :/ I assume you'd want to calculate W to find R ...
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    In our working out do we need to show the steps to solve quadratic equations or can we just our calculator to get the answer for it
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    (Original post by fpmaniac)
    I dont understand what you do sorry. What do you o with the v
    Okay tell me which part you dont understand out of these steps...

    r= (5-3t)i + (t-3)j

    When moving parallel, it has to be moving directly right or left, for example, (5i 0j)

    so the j component must equal zero

    t-3 = 0
    t=3 when moving parallel
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    (Original post by Not_a_horse)
    https://drive.google.com/file/d/0B1Z...w?pref=2&pli=1
    Question 3, if I find W first then use it to calculate R, will I still get full marks, because the mark scheme says not.
    Uhhhhh, I just spent like 10 minutes trying to see how you can do it without doing part ii first and I just checked the mark scheme... It doesn't say anywhere that you can't find W first????????? Name:  kik.JPG
Views: 91
Size:  31.4 KB
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    (Original post by Marccs)
    Can anyone help me with this question on vectors
    Use the formula - velocity = speed x direction x (1/magnitude of direction) then use r=ro + vt
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    (Original post by Wongsta)
    In our working out do we need to show the steps to solve quadratic equations or can we just our calculator to get the answer for it
    Best to show how you got the answer (whether that be by factorisation, completing the square or quadratic formula).
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    (Original post by Someboady)
    Zacken
    Is this true? :/ I assume you'd want to calculate W to find R ...
    No, lol, of course you'd get the marks...
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    (Original post by Wongsta)
    In our working out do we need to show the steps to solve quadratic equations or can we just our calculator to get the answer for it
    Show your working.

    (Original post by Don Pedro K.)
    Uhhhhh, I just spent like 10 minutes trying to see how you can do it without doing part ii first and I just checked the mark scheme... It doesn't say anywhere that you can't find W first????????? Name:  kik.JPG
Views: 91
Size:  31.4 KB
    You'll get the marks if you find W first.
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    (Original post by candol)
    part a) suvat
    s=h
    A=-9.8
    t=5
    u=20

    partb)
    Find V using suvat for the first ball
    You can now work out 3/4 v for the second ball
    Do suvat with v=3/4V, u=w, a=9.8, s= height found from part a
    thanks
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    (Original post by Don Joiner)
    Can anyone do this momentum/impulse question?

    The mark scheme shows:

    33/5mu = 2m(-v--4u)

    I don't get how they've got both the 4u and the v as negative since the question States P is moving due east?

    I can't make sense of it


    Posted from TSR Mobile
    question?
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    (Original post by KloppOClock)
    question?
    Dam I forgot; here:

    Name:  ImageUploadedByStudent Room1465326559.440596.jpg
Views: 122
Size:  140.4 KB


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    (Original post by Zacken)
    Show your working.



    You'll get the marks if you find W first.
    Yeah, the OP claimed that the mark scheme would not allow you to find W first before finding R :P
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    What happens when it says 'when C is at the point of tilting'??
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    (Original post by NigelK98)
    What happens when it says 'when C is at the point of tilting'??
    the reaction at the other support (not c) is zero
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    (Original post by Don Joiner)
    Dam I forgot; here:

    Name:  ImageUploadedByStudent Room1465326559.440596.jpg
Views: 122
Size:  140.4 KB


    Posted from TSR Mobile
    Yeah P is moving due east but it can be convinced to move due west with enough force from Q right..
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    (Original post by NigelK98)
    What happens when it says 'when C is at the point of tilting'??
    Nigel is that you??
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    (Original post by Don Joiner)
    Can anyone do this momentum/impulse question?

    The mark scheme shows:

    33/5mu = 2m(-v--4u)

    I don't get how they've got both the 4u and the v as negative since the question States P is moving due east?

    I can't make sense of it


    Posted from TSR Mobile
    They set west as the positive direction, you can set east as positivw direction and you'd get the same answer
 
 
 
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