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PROBLEM 18.95
Two disks, each of mass 5 kg and radius 300 mm, spin as shown at
the rate 11200 rpm
about a rod AB of negligible mass which
rotates about the horizontal z axis at the rate 260 rpm.
(a) Determine the dynamic reactions at points C and D. (b) Solve part
a assuming that the direction of spin of disk A is reversed.
PROBLEM 18.95 (Continued)
2
(b) For disk A: 12 1 2
,
AAyz
II
j
kH
j
k
1, 0
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
PROBLEM 18.96
Two disks, each of mass 5 kg and radius 300 mm, spin as shown at
the rate 11200 rpm
about a rod AB of negligible mass which
rotates about the horizontal z axis at the rate 2.
Determine the
maximum allowable value of 2
if the magnitudes of the dynamic
reactions at points C and D are not to exceed 350 N each.
PROBLEM 18.96 (Continued)
2
PROBLEM 18.97
A stationary horizontal plate is attached to the ceiling by means of a
fixed vertical tube. A wheel of radius a and mass m is mounted on a light
axle AC which is attached by means of a clevis at A to a rod AB fitted
inside the vertical tube. The rod AB is made to rotate with a constant
angular velocity causing the wheel to roll on the lower face of the
stationary plate. Determine the minimum angular velocity for which
contact is maintained between the wheel and the plate. Consider the
particular cases (a) when the mass of the wheel is concentrated in the
rim, (b) when the wheel is equivalent to a thin disk of radius a.
PROBLEM 18.97 (Continued)
Equating moments about A:
()G
RW
R
ijH
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
PROBLEM 18.98
Assuming that the wheel of Problem 18.97 weights 8 lb, has a radius a 4
in. and a radius of gyration of 3 in., and that R 20 in., determine the
force exerted by the plate on the wheel when 25 rad/s.
PROBLEM 18.97 A stationary horizontal plate is attached to the ceiling
by means of a fixed vertical tube. A wheel of radius a and mass m is
mounted on a light axle AC which is attached by means of a clevis at A to
a rod AB fitted inside the vertical tube. The rod AB is made to rotate with
a constant angular velocity causing the wheel to roll on the lower face
of the stationary plate. Determine the minimum angular velocity for
which contact is maintained between the wheel and the plate. Consider
the particular cases (a) when the mass of the wheel is concentrated in the
rim, (b) when the wheel is equivalent to a thin disk of radius a.
PROBLEM 18.98 (Continued)
Taking moments about A:
()
G
RDW
ijjH
PROBLEM 18.99
A thin disk of mass 4 kgm
rotates with an angular velocity 2
with respect to arm ABC, which itself rotates with an angular
velocity 1
about the y axis. Knowing that
5 rad/s
and
215 rad/s
and that both are constant, determine the force-couple
system representing the dynamic reaction at the support at A.
22
4
1(4)(0.150 m) 0.0225 kg m
xy
PROBLEM 18.99 (Continued)
(4)( 11.25 ) (45 N)
C
m aii
Free body and kinetic diagrams
