This preview shows pages 1–4. Sign up to view the full content.
For 3D moments I will use r cross F [][][] [][]NikjkMNmkjixjiMNkjiFmkjirxFrMPPABABA720720)120(60)(6003006002.12.060030060002.12.0--+--=-++=-+=++==Combining Similar terms []NmkjiMP660120720-+-=Want to find moment about x-axis Convert to meters [][][] [][]NmijikMNmkjixkjMNkjiFmkjirxFrMPPABABA)6.3()2.1(15.0)3.0()(21243.0075.021243.0075.00--++-=+-+=+-=++==Combining Similar terms []NmkjiMP3.02.175.3-+=Need only i term or dot with unit vector i. NmMP75.3=
This preview
has intentionally blurred sections.
Sign up to view the full version.
Sum the moments about point A They have to be equal to zero so there is no couple [][][] [][]NmmkNkNmmNjixjiMNNjiFmmjjjirxFrMPABABA11253.430)(15753.4301530sin50252530cos500-=+--==+=----===ooAll Similar terms drop k and equate NNNmmNmm0.26)(1125)(3.43==Sum the moments about point A Goes to zero, neglect force at B 0=∑AM