sm9 89

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PROBLEM (*9.89) Redo Prob. 9.88, assuming that the tensions on the pulley C are in the horizontal
(z) direction.
*SOLUTION
Now Fig. S9.88a (see: Solution of Prob. 9.88) becomes as shown below.
From statics:
0.4 1.2
yy
AkipsBkips==
1.2 0.4
zz
AkipsBkips==
The critical section is just to the right of C (or just to the left of D). Thus
222 2 2 2
21.6 7.2 4.8 23.27 .
zy
M
MT kipin++= + + = ⋅
Applying Eq. (9.32):
3
33
16 10 (21.6 23.21) 2.25 .
(20 10 )
din
π
×
=+=
×
Use a
14
2.in− diameter shaft.
x
y
A
C
B
M
y
x
x
M
z
z
D
3 ft
B
z
A
z
T
x
(d)
(
a
)
1.6 kips 1.6 kips
4.8 , kip
⋅
in.
A
y
21.6 ki
p
⋅
in.
1.5 ft
1.8x12=21.6 ki
p
⋅
in.
B
y
4.8 kip⋅in.
(c)
4.8 ki
p
⋅
in.
(
b
)
0.6x12=7.2 kip
⋅
in.