Engineering Drawing Dimensioning

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engineering mechanics question?

Hey im having trouble with these questions help with either two would be greatly appreciated.

http://img194.imageshack.us/img194/308/1010s.jpg

For question 1 i have to find the resultant of the two forces acting on the rigid plane...So what i have done is drawn a force triangle and from there i used the law of cosins to find the magnitude of the resultant however my answer does not seem corect. Are the dimensions given in the diagram not needed at all because i didnt use them when obtaining my answer?

For the second question i have no idea any help i would greatly appreciated, thanks

Second problem

consider a line parallel to AC starting at B.. BD (D is to the right of B)

Angle DBC = 45
Angle ABC = 180 -105 =75

let force along AB = F1
force perpendicular to AB = F2
force along BC = F3
force perpendicular to BC = F4

sum of all forces parallel to BD = 0 (equilibrium)

3 + F3 cos45 + F4 cos45 + F1 cos 60 -F2sin 15 = 0

similarly sum of forces perpendicular to BD = 0
similarly sum of forces parallel to AD = 0
similarly sum of forces perpendicular to AD = 0

u have 4 equations....solve for F1,F3

SolidWorks 2011- Dimension Spacing


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