1. Problem 3.152 y The frame ACD is hinged at A Gz x
0.875 m
0.75 m
0.5 m
0.35 m
0.925 m A B O C D P H G
The frame ACD is hinged at A
and D and is supported by a
cable which passes through a
ring at B and is attached to
hooks at G and H. Knowing
that the tension in the cable is
450 N, determine the moment
about the diagonal AD of the
force exerted on the frame by
portion BH of the cable.

2. Solving Problems on Your Ownz x
0.875 m
0.75 m
0.5 m
0.35 m
0.925 m A B O C D P H G
Solving Problems on Your Own
The frame ACD is hinged at A
and D and is supported by a
cable which passes through a
ring at B and is attached to
hooks at G and H. Knowing
that the tension in the cable is
450 N, determine the moment
about the diagonal AD of the
force exerted on the frame by
portion BH of the cable.
Problem
1. Determine the moment MOL of a force about a given axis OL.
MOL is defined as
MOL = l . MO = l . ( r x F )
where l is the unit vector along OL and r is a position vector from
any point on the line OL to any point on the line of action of F.

3. TBH = ( 0.375 i + 0.75 j _ 0.75 k ) MAD = l AD . ( rB/A x TBH )y z
0.875 m
0.75 m
0.5 m
0.35 m
0.925 m A B O C D P H G
TBH
lAD
rB/A x
Problem Solution
Determine the moment MAD of a
force about line AD.
MAD = l AD . ( rB/A x TBH )
Where
lAD = (4 i _ 3 k)
rB/A = (0.5 m ) i 1 5
dBH = ( )2 + ( 0.75 )2 + ( _ 0.75 )2 = m
TBH = ( i j _ 0.75 k )
= ( 150 N) i + ( 300 N) j _ ( 300 N) k
450 N
1.125

4. MAD = lAD . ( rB/A x TBH ) TBH lAD 4 0 _3 MAD 0.5 0 0 1 MAD =y z
0.875 m
0.75 m
0.5 m
0.35 m
0.925 m A B O C D P H G
TBH
lAD
rB/A x
Problem Solution
Finally:
MAD = lAD . ( rB/A x TBH )
MAD = 1 5 _3
_300 1 5
= [(_3)(0.5)(300)]
MAD = _ 90 N.m