COSMOS: Complete Online Solutions Manual Organization System
Chapter 3, Solution 95.
Have ΣF :
F = FD
JJG
AI
where F = F
AI
= ( 63 lb )
14.4i − 4.8j + 7.2k
(14.4 )2 + ( − 4.8)2 + ( 7.2 )2
F = ( 54.0 lb ) i − (18.00 lb ) j + ( 27.0 lb ) k
So that
Have ΣM D :
M + rI /O × F = M D
JJJG
AC
where M = M
AC
= ( 560 lb ⋅ in.)
9.6 i − 7.2 k
( 9.6 )2 + ( − 7.2 )2
= ( 448 lb ⋅ in.) i − ( 336 lb ⋅ in.) k
Then M D
i
j
k
= ( 448 lb ⋅ in.) i − ( 336 lb ⋅ in.) k + 0 0 14.4 lb ⋅ in.
54 −18 27
= ( 448 lb ⋅ in.) i − ( 336 lb ⋅ in.) k + ( 259.2 lb ⋅ in.) i + ( 777.6 lb ⋅ in.) j
or
.
M D = ( 707 lb ⋅ in.) i + ( 778 lb ⋅ in.) j − ( 336 lb ⋅ in.) k