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Additional Math Help HERE ONLY...!

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cooldude:

--- Quote from: syedz123 on May 31, 2010, 04:21:56 pm ---am quite a week student in add math...can sum1 plz xplain question 12 second one on velocity for me...its may/june 09 p1...


I still have accouting,chems litt n econs n add math left so i wont b able to do alot of pp for add maths...can any1 plz recommend which yrs i shuld do..like gud hard papers...atleast 3 yrs plz apart 4rm 09 Thanks

--- End quote ---

i) 0=kcos4t
cos4t=0
90=4t
t=22.5 sec
ii) dv/dt=a=-4ksin4t
iii) 12=4k as sin(4*(3/8))=-1
k=3
iv) u just have to sketch the graph of 3cos4t
v) integrate the expression for velocity-->
x=3sin4t/4+k
however since at the origin the displacement is 0, therefore k=0
now substitute t=pi/24
x=0.375 m

Ghost Of Highbury:

--- Quote from: syedz123 on May 31, 2010, 04:21:56 pm ---am quite a week student in add math...can sum1 plz xplain question 12 second one on velocity for me...its may/june 09 p1...


I still have accouting,chems litt n econs n add math left so i wont b able to do alot of pp for add maths...can any1 plz recommend which yrs i shuld do..like gud hard papers...atleast 3 yrs plz apart 4rm 09 Thanks

--- End quote ---

i) substitute 0 for velocity.. 0 = cos 4t

  4t = y

   cos y = 0

     y = cos-1 0 = 90

here its 90 degrees, but v gotta take it in radians, so Pi radians = 180 degree

4t = 0.5pi radians
t = pi/8

t = pi/4

ii) differentiate v = k cos 4t

     k = a
     cos 4t = b

     d/dx(a) = 0

     d/dx(b) = -4sin4t

     dv/dx = a(db) + b(da) = -4ksin4t + 0 = -4k sin 4t

iii)  
    k = 3

iv) make a table and plot the points.

v) integration of 3cos4t with limits pi/24 and 0

                  

  

syedz123:
Thanks guys  :D

J.Darren:

--- Quote from: A@di on May 31, 2010, 05:41:21 pm ---
here its 90 degrees, but v gotta take it in radians, so Pi radians = 180 degree

4t = 180

t = pi/4
--- End quote ---
Cosine equals to 0 at 90 degreees (first instantaneously at rest) / 0.5 pi radian, 90 / 4 = 22.5 degrees / 0.125 pi radian :o

Ghost Of Highbury:

--- Quote from: J.Darren on May 31, 2010, 06:23:57 pm ---Cosine equals to 0 at 90 degreees (first instantaneously at rest) / 0.5 pi radian, 90 / 4 = 22.5 degrees / 0.125 pi radian :o

--- End quote ---

my bad.edited. thanks

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