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PROBLEM 3.68
In Problem 3.59, determine the perpendicular distance
between cable AE and the line joining Points D and B.
PROBLEM 3.59 The triangular plate ABC is supported by
ball-and-socket joints at B and D and is held in the position
shown by cables AE and CF. If the force exerted by cable
AE at A is 55 N, determine the moment of that force about
the line joining Points D and B.
PROBLEM 3.69
In Problem 3.60, determine the perpendicular distance
between cable CF and the line joining Points D and B.
PROBLEM 3.60 The triangular plate ABC is supported by
ball-and-socket joints at B and D and is held in the position
shown by cables AE and CF. If the force exerted by cable
CF at C is 33 N, determine the moment of that force about
the line joining Points D and B.
PROBLEM 3.70
Two 80-N forces are applied as shown to the corners B and D of
a rectangular plate. (a) Determine the moment of the couple
formed by the two forces by resolving each force into horizontal
and vertical components and adding the moments of the two
resulting couples. (b) Use the result obtained to determine the
perpendicular distance between lines BE and DF.
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
PROBLEM 3.71
Two parallel 40-N forces are applied to a lever as shown.
Determine the moment of the couple formed by the two forces
(a) by resolving each force into horizontal and vertical
components and adding the moments of the two resulting
couples, (b) by using the perpendicular distance between the
two forces, (c) by summing the moments of the two forces
about Point A.
PROBLEM 3.72
Four 1
1
2
-in.-diameter pegs are attached to a board as shown.
Two strings are passed around the pegs and pulled with the
forces indicated. (a) Determine the resultant couple acting on
the board. (b) If only one string is used, around which pegs
should it pass and in what directions should it be pulled to
create the same couple with the minimum tension in the string?
(c) What is the value of that minimum tension?
PROBLEM 3.73
Four pegs of the same diameter are attached to a board as
shown. Two strings are passed around the pegs and pulled with
the forces indicated. Determine the diameter of the pegs
knowing that the resultant couple applied to the board is
1132.5 lb·in. counterclockwise.
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
PROBLEM 3.74
A piece of plywood in which several holes are being drilled
successively has been secured to a workbench by means of two
nails. Knowing that the drill exerts a 12-N∙m couple on the
piece of plywood, determine the magnitude of the resulting
forces applied to the nails if they are located (a) at A and B,
(b) at B and C, (c) at A and C.
PROBLEM 3.75
The two shafts of a speed-reducer unit are subjected to
couples of magnitude M1 = 15 lb∙ft and M2 = 3 lb∙ft,
respectively. Replace the two couples with a single
equivalent couple, specifying its magnitude and the
direction of its axis.
PROBLEM 3.76
If
0,P=
replace the two remaining couples with a single
equivalent couple, specifying its magnitude and the
direction of its axis.
PROBLEM 3.77
If
20 lb,P=
replace the three couples with a single
equivalent couple, specifying its magnitude and the
direction of its axis.
