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Statics 2e 303
Problem 3.35
Determine the largest weight
W
that may be supported if the failure strengths
of the cables and bars are
Member Strength
AC 600 lb
AE 250 lb
CD 300 lb
AB 2000 lb tension & 700 lb compression
BC 1000 lb tension & 300 lb compression
Problem 3.36
Determine the largest weight
W
that may be supported if the failure strengths of
the cables and bars are
Member Strength
AB 3:5 kN
BC 3 kN
CD 2:5 kN
BE 3:7 kN tension & 1:8 kN compression
CE 4:7 kN tension & 2:8 kN compression
Problem 3.37
The system shown consists of cables
AB
and
AC
, horizontal cable
CE
, and vertical bar
CD
. If the cables
and bar have the failure strengths shown, determine the largest load
P
that can be supported by the system.
Member Strength
AB 300 lb
AC 300 lb
CE 200 lb
CD 600 lb tension & 200 lb compression
Problem 3.38
The cable-pulley systems shown are used to support a
weight W.
(a)
Assuming the segments of cable between the pulleys
are vertical, determine the cable tension
T
in terms
of W.
(b)
If the segments of cable between the pulleys are not
precisely vertical, will your answer to Part (a) be
affected? Explain.
Problem 3.39
The cable-pulley systems shown are used to support a weight
W
. Determine the cable
tension Tin terms of W.
Problem 3.40
The hoist shown is used in a machine shop to position heavy workpieces in a
lathe. If the cable between pulleys
A
and
B
can support a force of
300 lb
, all
other cables can support a force of
500 lb
, and bar
CE
can support a compressive
force of 600 lb, determine the largest weight Wthat may be lifted.
Problem 3.41
The cable system shown is used to help support a water pipe that crosses a
creek. The water pipe applies forces
WA
and
WD
to the ends of cables
AB
and
DE
, respectively, where it is known that
WACWDD800 lb
. If cable
BE
is
horizontal and cables
AB
and
DE
are vertical, determine the tension in each
cable and the forces WAand WD.
Problem 3.42
Compared to the cable system shown in Prob. 3.41, the system shown here may
provide for more uniform support of a water pipe that crosses a creek. The
water pipe applies forces
WA
,
WD
, and
WG
to the ends of cables
AB
,
DE
, and
GH
, respectively, where it is known that
WACWDCWGD800 lb
. If cables
AB
,
DE
, and
GH
are vertical, determine the tension in each cable and the
forces WA,WD, and WG.
Problem 3.43
The frictionless slider
B
has a frictionless pulley mounted to it, around which
is wrapped a cable that supports weight
WD30 lb
as shown. The pulley at
D
is also frictionless, and member BE is a bar.
(a)
If
˛D20ı
, determine the force in bar
BE
and the reaction between the
slider and bar AC .
(b)
Determine the value of
˛
that will provide for the smallest force in bar
BE, and determine the value of this force.
Problem 3.44
If WD225 N, determine the tension in cable BCA and angle .
Problem 3.45
Consider a contiguration where
D30ı
. Is this contiguration possible?
Explain.
Problem 3.46
Determine the weights
W1
and
W2
needed for the pulley-cable structure to have
the equilibrium contiguration shown.
Problem 3.47
An object with
100 lb
weight is supported by cable
ABC
where the pulley at
B
is frictionless. For the cable length and value of
h
given below, determine
the force supported by cable
ABC
and the value of
d
when the system is in
equilibrium. Neglect the size of the pulley. Use of a computer mathematics
program such as Mathematica or Maple is necessary. Hint: The solution for
d
is an integer number.
Cable ABC has 85 in:length and hD8in:
Problem 3.48
An object with
100 lb
weight is supported by cable
ABC
where the pulley at
B
is frictionless. For the cable length and value of
h
given below, determine
the force supported by cable
ABC
and the value of
d
when the system is in
equilibrium. Neglect the size of the pulley. Use of a computer mathematics
program such as Mathematica or Maple is necessary. Hint: The solution for
d
is an integer number.
Cable ABC has 195 in:length and hD36 in:
Problem 3.49
Load
P
is supported by cables
AB
,
AC
, and
AD
. Cable
AC
is vertical. When
you solve for these cable tensions, a “problem” arises. Describe this problem
and, if possible, its physical signiticance.
