PROBLEM 6.151
Since the brace shown must remain in position even when the magnitude of
P
is
very small, a single safety spring is attached at D and E. The spring DE has a
constant of 50 lb/in. and an unstretched length of 7 in. Knowing that l = 10 in. and
that the magnitude of
P
is 800 lb, determine the force
Q
required to release the
brace.
PROBLEM 6.152
The specialized plumbing wrench shown is used in confined areas (e.g.,
under a basin or sink). It consists essentially of a jaw BC pinned at B to a
long rod. Knowing that the forces exerted on the nut are equivalent to a
clockwise (when viewed from above) couple of magnitude 135 lb in.,
determine (a) the magnitude of the force exerted by pin B on jaw BC,
(b) the couple
M0
that is applied to the wrench.
PROBLEM 6.153
The motion of the bucket of the front-end loader
shown is controlled by two arms and a linkage
that are pin-connected at D. The arms are located
symmetrically with respect to the central,
vertical, and longitudinal plane of the loader; one
arm AFJ and its control cylinder EF are shown.
The single linkage GHDB and its control cylinder
BC are located in the plane of symmetry. For the
position and loading shown, determine the force
exerted (a) by cylinder BC, (b) by cylinder EF.
PROBLEM 6.154
The bucket of the front-end loader shown carries a
3200–lb load. The motion of the bucket is
controlled by two identical mechanisms, only
one of which is shown. Knowing that the
mechanism shown supports one-half of the
3200-lb load, determine the force exerted (a) by
cylinder CD, (b) by cylinder FH.
PROBLEM 6.155
The telescoping arm ABC is used to provide an elevated
platform for construction workers. The workers and the
platform together have a mass of 200 kg and have a
combined center of gravity located directly above C. For the
position when
20, determine (a) the force exerted at B
by the single hydraulic cylinder BD, (b) the force exerted on
the supporting carriage at A.
PROBLEM 6.156
The telescoping arm ABC of Prob. 6.155 can be lowered
until end C is close to the ground, so that workers can easily
board the platform. For the position when
= 20,
determine (a) the force exerted at B by the single hydraulic
cylinder BD, (b) the force exerted on the supporting carriage
at A.
PROBLEM 6.157
The motion of the backhoe bucket
shown is controlled by the hydraulic
cylinders AD, CG, and EF. As a result
of an attempt to dislodge a portion of a
slab, a 2-kip force
P
is exerted on the
bucket teeth at J. Knowing that
45,
determine the force exerted by each
cylinder.
21.801
PROBLEM 6.157 (Continued)
16.7126
EF
EF
PROBLEM 6.158
Solve Problem 6.157 assuming that the
2-kip force
P
acts horizontally to the
right (
0).
PROBLEM 6.157
The motion of the
backhoe bucket shown is controlled by
the hydraulic cylinders AD, CG, and
EF. As a result of an attempt to
dislodge a portion of a slab, a 2-kip
force
P
is exerted on the bucket teeth at
J. Knowing that
45, determine the
force exerted by each cylinder.
PROBLEM 6.158 (Continued)
16.7126
EF
EF