Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
PROBLEM 8.24
End A of a slender, uniform rod of length L and weight W bears on a surface as
shown, while end B is supported by a cord BC. Knowing that the coefficients
of friction are
0.40
s
and
0.30,
k
determine (a) the largest value of
for which motion is impending, (b) the corresponding value of the tension in the
cord.
PROBLEM 8.25
A 6.5-m ladder AB leans against a wall as shown. Assuming that the coefficient
of static friction
s
is zero at B, determine the smallest value of
s
at A for
which equilibrium is maintained.
PROBLEM 8.26
A 6.5-m ladder AB leans against a wall as shown. Assuming that the coefficient
of static friction
s
is the same at A and B, determine the smallest value of
s
for which equilibrium is maintained.
PROBLEM 8.27
The press shown is used to emboss a small seal at E.
Knowing that the coefficient of static friction between the
vertical guide and the embossing die D is 0.30, determine the
force exerted by the die on the seal.
PROBLEM 8.28
The machine base shown has a mass of 75 kg and is fitted with skids at A
and B. The coefficient of static friction between the skids and the floor is
0.30. If a force
P
of magnitude 500 N is applied at corner C, determine the
range of values of θ for which the base will not move.
PROBLEM 8.29
The 50-lb plate ABCD is attached at A and D to collars that can slide
on the vertical rod. Knowing that the coefficient of static friction is
0.40 between both collars and the rod, determine whether the plate is
in equilibrium in the position shown when the magnitude of the
vertical force applied at E is (a)
0,P
(b)
20 lb.P
PROBLEM 8.30
In Problem 8.29, determine the range of values of the magnitude P of
the vertical force applied at E for which the plate will move
downward.
PROBLEM 8.29
The 50-lb plate ABCD is attached at A and D to
collars that can slide on the vertical rod. Knowing that the coefficient
of static friction is 0.40 between both collars and the rod, determine
whether the plate is in equilibrium in the position shown when the
magnitude of the vertical force applied at E is (a)
0,P
(b)
20 lb.P
PROBLEM 8.30 (Continued)
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
PROBLEM 8.31
A window sash weighing 10 lb is normally supported by two 5-lb sash
weights. Knowing that the window remains open after one sash cord
has broken, determine the smallest possible value of the coefficient of
static friction. (Assume that the sash is slightly smaller than the frame
and will bind only at Points A and D.)
PROBLEM 8.32
A 500-N concrete block is to be lifted by the pair of tongs shown.
Determine the smallest allowable value of the coefficient of static
friction between the block and the tongs at F and G.
