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hi, i have tried to work this question out it seems so easy but i must be missing something.
determine the magnitude and directional sense of the moment of the force at A about point O.
http://img229.imageshack.us/img229/9895/statics19hv.jpg
these are 3 of my calculations for the question
F = 520 sin 30(6) - 520 cos 30(0)
F = 1560N or 1.56kN
also
F = 520 sin 120(6) - 0
F = 2.7kN
i also tried using vectors
r = {6i- 0j}m
F = {520sin30i - 520cos30j}N
= {260i - 450.33j}
The moment is therefore
Mo = r x F = 0i - 0j + [6(-450.33)-(0)(200)]k
= {-2.7k} kN.m
the answer in the books telling me 2.88 kN.m can someone point me to where I am going wrong i have obviously misunderstood something
thanks
determine the magnitude and directional sense of the moment of the force at A about point O.
http://img229.imageshack.us/img229/9895/statics19hv.jpg
these are 3 of my calculations for the question
F = 520 sin 30(6) - 520 cos 30(0)
F = 1560N or 1.56kN
also
F = 520 sin 120(6) - 0
F = 2.7kN
i also tried using vectors
r = {6i- 0j}m
F = {520sin30i - 520cos30j}N
= {260i - 450.33j}
The moment is therefore
Mo = r x F = 0i - 0j + [6(-450.33)-(0)(200)]k
= {-2.7k} kN.m
the answer in the books telling me 2.88 kN.m can someone point me to where I am going wrong i have obviously misunderstood something
thanks
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