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    It says the motion of a particle (position vector) r(t) is:

    r(t) = 2cos(6t)i+2sin(4t)j

    1. It asks me to describe the motion in my own words, so what do I actually have to say?

    Is it going 2cos(6t) in the i and 2sin(4t) in the j direction?

    2. How are the acceleration and r(t) = 2cos(6t)i+2sin(4t)j related?
    Do i just say you differentiate r(t) twice to get the acceleration?
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    (Original post by rpan161)
    It says the motion of a particle (position vector) r(t) is:

    r(t) = 2cos(6t)i+2sin(4t)j

    1. It asks me to describe the motion in my own words, so what do I actually have to say?

    Is it going 2cos(6t) in the i and 2sin(4t) in the j direction?

    2. How are the acceleration and r(t) = 2cos(6t)i+2sin(4t)j related?
    Do i just say you differentiate r(t) twice to get the acceleration?
    If my memory doesn't fail me that would be some kind of circular/elliptical graph if you plotted it on axis.

    As for the second bit, I think so, at least that's what I'd do (maybe stand back for a bit after you've differentiated twice just to see if there are any obvious comments you can make on it).
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    Thanks, how would i plot it? like t=0, 1, 2 etc..?
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    (Original post by rpan161)
    Thanks, how would i plot it? like t=0, 1, 2 etc..?
    I'm sure there's a more efficient way but I can't really remember it at the moment, so try plotting it as you said, just set t=0, 1, 2, 3, ...
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    hmm okay thanks, i'll see how it goes
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    If you're going to plot the function, I'd be inclined to use multiples and fractions of pi as the values for t.

    Note: This won't be a trivial circle or ellipse. In fact I'm slightly surprised it's M1, given the difficulty of most of the other M1 questions I've seen on here.
 
 
 
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