978-0073398242 Chapter 3 Solution Manual Part 14

subject Type Homework Help
subject Pages 9
subject Words 1654
subject Authors Brian Self, David Mazurek, E. Johnston, Ferdinand Beer, Phillip Cornwell

Unlock document.

This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
page-pf1
PROBLEM 3.122
In order to unscrew the tapped faucet A, a
plumber uses two pipe wrenches as shown.
By exerting a 40-lb force on each wrench, at
a distance of 10 in. from the axis of the pipe
and in a direction perpendicular to the pipe
and to the wrench, he prevents the pipe from
rotating, and thus avoids loosening or further
tightening the joint between the pipe and the
tapped elbow C. Determine (a) the angle θ
that the wrench at A should form with the
vertical if elbow C is not to rotate about the
vertical, (b) the force-couple system at C
equivalent to the two 40-lb forces when this
condition is satisfied.
page-pf2
PROBLEM 3.123
Assuming θ = 60° in Prob. 3.122, replace the
two 40-lb forces with an equivalent force-
couple system at D and determine whether
the plumber’s action tends to tighten or
loosen the joint between (a) pipe CD and
elbow D, (b) elbow D and pipe DE.
Assume all threads to be right-handed.
PROBLEM 3.122 In order to unscrew the
tapped faucet A, a plumber uses two pipe
wrenches as shown. By exerting a 40-lb
force on each wrench, at a distance of 10 in.
from the axis of the pipe and in a direction
perpendicular to the pipe and to the wrench,
he prevents the pipe from rotating, and thus
avoids loosening or further tightening the
joint between the pipe and the tapped elbow
C. Determine (a) the angle θ that the
wrench at A should form with the vertical if
elbow C is not to rotate about the vertical,
(b) the force-couple system at C equivalent
to the two 40-lb forces when this condition
is satisfied.
page-pf3
PROBLEM 3.124
Four forces are applied to the machine component
ABDE as shown. Replace these forces with an
equivalent force-couple system at A.
page-pf4
PROBLEM 3.125
A blade held in a brace is used to tighten a screw at
A. (a) Determine the forces exerted at B and C,
knowing that these forces are equivalent to a force-
couple system at A consisting of R = (25 N)i + Ryj
+ Rzk and M
R
A
= (13.5 N·m)i. (b) Find the
corresponding values of Ry and Rz. (c) What is the
orientation of the slot in the head of the screw for
which the blade is least likely to slip when the brace
is in the position shown?
page-pf5
PROBLEM 3.126
A mechanic uses a crowfoot wrench to loosen a bolt at C.
The mechanic holds the socket wrench handle at Points A
and B and applies forces at these points. Knowing that
these forces are equivalent to a force-couple system at C
consisting of the force
(8 lb) + (4 lb)= C ik
and the
couple
(360 lb ·
C=
M
in.)i, determine the forces applied at
A and at B when
2 lb.
z
A=
yy
page-pf6
PROBLEM 3.126 (Continued)
page-pf7
PROBLEM 3.127
Three children are standing on a
5 5-m
×
raft. If the
weights of the children at Points A, B, and C are 375 N,
260 N, and 400 N, respectively, determine the magnitude
and the point of application of the resultant of the three
weights.
page-pf8
PROBLEM 3.128
Three children are standing on a
5 5-m raft.×
The
weights of the children at Points A, B, and C are 375 N,
260 N, and 400 N, respectively. If a fourth child of weight
425 N climbs onto the raft, determine where she should
stand if the other children remain in the positions shown
and the line of action of the resultant of the four weights
is to pass through the center of the raft.
page-pf9
PROBLEM 3.129
Four signs are mounted on a frame spanning a
highway, and the magnitudes of the horizontal
wind forces acting on the signs are as shown.
Determine the magnitude and the point of
application of the resultant of the four wind forces
when
1 ft
a=
and
12 ft.b=
page-pfa
PROBLEM 3.130
Four signs are mounted on a frame spanning a
highway, and the magnitudes of the horizontal
wind forces acting on the signs are as shown.
Determine a and b so that the point of application
of the resultant of the four forces is at G.

Trusted by Thousands of
Students

Here are what students say about us.

Copyright ©2022 All rights reserved. | CoursePaper is not sponsored or endorsed by any college or university.