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Problem 3.133
Frictionless sliders
B
and
C
have frictionless pulleys mounted to them, and
are connected by a spring with stiffness
kD12 N=mm
. Around the pulleys is
wrapped a cable that supports a weight WD100 N. Member CE is a bar.
(a) If ˛D30ı, determine the force in bar CE and the motion ıof slider B.
(b)
Determine the value of
˛
that will provide for the smallest force in bar
CE, and determine this force.
Problem 3.134
A weight
W
is supported by four cables. Points
B
and
C
lie in the
y´
plane. If
WD8kN, determine the force supported by each cable.
Solution
Problem 3.135
A weight
W
is suspended by four cables. Points
B
and
C
lie in the
y´
plane. If
the allowable strength of each cable is as specified below, determine the largest
allowable weight Wthat can be supported.
Cable Strength
AB 12 kN
AC 10 kN
AD 5 kN
AE 15 kN
Solution
Problem 3.136
Repeat Prob. 3.134 with points Band Chaving coordinates B.0; 6; 3/ m and C.0; 6; 7/ m.
Solution
Problem 3.137
Repeat Prob. 3.135 with points Band Chaving coordinates B.0; 6; 3/ m and C.0; 6; 7/ m.
CTAB
6
9CTAC
6
11 CTAD .0/ TAE .1/O|
3
9CTAC 7
11 CTAD .0/ CTAE .0/O
(5)
if TAD D5kN;then WD5kN;
(7)
Problem 3.138
A winch at point
B
is used to slowly slide a box up a chute
CD
in a warehouse.
The box weighs
600 lb
and fits loosely against the walls of the chute and slides
with no friction. For the position of the box given below, determine the force in
the cable and the reactions between the box and chute. The chute is parallel to
the
x´
plane. Neglect the size of the box and winch. The box is 1/5 the distance
up the chute from point C.
Solution
E
TAB DTAB ErAB
rAB DTAB 141 O{100 O|C120 O
k
p44;281 ;(3)
Problem 3.139
A winch at point
B
is used to slowly slide a box up a chute
CD
in a warehouse.
The box weighs
600 lb
and fits loosely against the walls of the chute and slides
with no friction. For the position of the box given below, determine the force in
the cable and the reactions between the box and chute. The chute is parallel to
the
x´
plane. Neglect the size of the box and winch. The box is 3/5 the distance
up the chute from point C.
Solution
E
TAB DTAB ErAB
rAB DTAB 93 O{100 O|C100 O
k
p28;649 ;(3)
Problem 3.140
The collars
B
and
E
each weigh
20 lb
and slide without friction on fixed bars
AC
and
DG
, respectively. Bar
AC
is parallel to the
´
axis and bar
DG
is
parallel to the
y
axis. For the value of
yE
given below, determine the force
P
needed for equilibrium, the force in cable
BE
, and the reactions between each
collar and rod. yED9in:
Problem 3.141
The collars
B
and
E
each weigh
20 lb
and slide without friction on fixed bars
AC
and
DG
, respectively. Bar
AC
is parallel to the
´
axis and bar
DG
is
parallel to the
y
axis. For the value of
yE
given below, determine the force
P
needed for equilibrium, the force in cable
BE
, and the reactions between each
collar and rod. yED13 in:
