PROBLEM 3.49
To loosen a frozen valve, a force F of magnitude 70 lb is
applied to the handle of the valve. Knowing that
25 ,
θ
= °
Mx
61lb ft,=−⋅
and
43 lb ft,
z
M=−⋅
determine
φ
and d.
PROBLEM 3.50
When a force F is applied to the handle of the valve
shown, its moments about the x and z axes are,
respectively,
77 lb ft
x
M=−⋅
and
81lb ft.
z
M=−⋅
For
27d=
in., determine the moment My of F about the y axis.
11
y zx
PROBLEM 3.50 (Continued)
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PROBLEM 3.51
To lift a heavy crate, a man uses a block and tackle attached to the
bottom of an I–beam at hook B. Knowing that the moments about
the y and the z axes of the force exerted at B by portion AB of the
rope are, respectively, 120 N ⋅ m and −460 N ⋅ m, determine the
distance a.
PROBLEM 3.52
To lift a heavy crate, a man uses a block and tackle attached to the
bottom of an I–beam at hook B. Knowing that the man applies a
195-N force to end A of the rope and that the moment of that force
about the y axis is 132 N ⋅ m, determine the distance a.
PROBLEM 3.53
A farmer uses cables and winch pullers B and E to plumb
one side of a small barn. If it is known that the sum of the
moments about the x–axis of the forces exerted by the
cables on the barn at Points A and D is equal to 4728 lb ⋅
ft, determine the magnitude of TDE when TAB = 255 lb.
PROBLEM 3.54
Solve Problem 3.53 when the tension in cable AB is 306
lb.
PROBLEM 3.53 A farmer uses cables and winch pullers
B and E to plumb one side of a small barn. If it is known
that the sum of the moments about the x–axis of the forces
exerted by the cables on the barn at Points A and D is equal
to 4728 lb ⋅ ft, determine the magnitude of TDE when
TAB = 255 lb.
Copyright © McGraw–Hill Education. Permission required for reproduction or display.
PROBLEM 3.55
The 23–in. vertical rod CD is welded to the midpoint C of
the 50–in. rod AB. Determine the moment about AB of the
235-lb force P.
PROBLEM 3.56
The 23–in. vertical rod CD is welded to the midpoint C of
the 50–in. rod AB. Determine the moment about AB of the
174-lb force Q.
PROBLEM 3.57
The frame ACD is hinged at A and D and is supported by a
cable that passes through a ring at B and is attached to
hooks at G and H. Knowing that the tension in the cable is
450 N, determine the moment about the diagonal AD of
the force exerted on the frame by portion BH of the cable.