PROBLEM 16.20 (Continued)
PROBLEM 16.20 (Continued)
PROBLEM 16.21
Draw the shear and bending–moment diagrams for the vertical rod
AB of Problem 16.16.
PROBLEM 16.16 Three bars, each of mass 3 kg, are welded
together and are pin–connected to two links BE and CF. Neglecting
the weight of the links, determine the force in each link immediately
after the system is released from rest.
PROBLEM 16.21 (Continued)
PROBLEM 16.22
Draw the shear and bending–moment diagrams for each of the bars
AB and BE of Prob. 16.14.
PROBLEM 16.14
Bars AB and BE, each of mass 4 kg, are welded together and are pin-
connected to two links AC and BD. Knowing that the assembly is
released from rest in the position shown and neglecting the masses of
the links, determine (a) the acceleration of the assembly, (b) the
forces in the links.
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PROBLEM 16.22 (Continued)
43
23
0.5 2 2
n
g
ma u gu
= =
( )
43 23
0.5 2
n
ug
F V gu
Σ= −=
23V gu=
()
22
3
2
8 2 3 /2 3
2
u
M M ug gu M guΣ= + = =−
PROBLEM 16.23
For a rigid body in translation, show that the system of the inertial terms consists of
vectors
()
i
m
∆a
attached to the various particles of the body, where
a
is the
acceleration of the mass center G of the body. Further show, by computing their
sum and the sum of their moments about G, that the inertial terms reduce to a
single vector
ma
attached at G.
PROBLEM 16.24
For a rigid body in centroidal rotation, show that the system of the inertial terms
consists of vectors
2
()
ii
m’−∆ r
ω
and
( )( )
ii
m’∆×ra
attached to the various particles
i
P
of the body, where
ω
and
a
are the angular velocity and angular acceleration of the
body, and where
i
‘r
denotes the position vector of the particle
i
P
relative to the mass
center G of the body. Further show, by computing their sum and the sum of their
moments about G, that the inertial terms reduce to a couple
.Ιa
PROBLEM 16.25
It takes 10 min for a 2.4–Mg flywheel to coast to rest from an angular velocity of 300 rpm. Knowing that the
radius of gyration of the flywheel is 1 m, determine the average magnitude of the couple due to kinetic
friction in the bearing.
PROBLEM 16.26
The rotor of an electric motor has an angular velocity of 3600 rpm when the load and power are cut off. The
120-lb rotor, which has a centroidal radius of gyration of 9 in., then coasts to rest. Knowing that kinetic
friction results in a couple of magnitude
2.5 lb ft⋅
exerted on the rotor, determine the number of revolutions
that the rotor executes before coming to rest.