Three identical circular disks are welded to the ends of three identical circular bars arranged in a common plane with the disks perpendicular to the bars. The bars are welded together at their intersection to form a rigid connection. Forces acting on each disk subject the bars to torsion. If one force is 28 lbs, the maximum shear stress in any bar is 4840 psi.

1. Three identical circular disks A, B, and C are welded
to the ends of three identical solid circular bars
(see figure). The bars lie in a common plane and the
disks lie in planes perpendicular to the axes of the
bars. The bars are welded at their intersection D to
form a rigid connection. Each bar has diameter
d1 = 0.5 in. and each disk has diameter d2 = 3.0 in.
Forces P1, P2, and P3 act on disks A, B, and C,
respectively, thus subjecting the bars to torsion.
If P1 = 28 lb, what is the maximum shear stress
tmax in any of the three bars?
R//tmax=4840 psi

3. A circular bar AB with ends fixed against rotation
has a hole extending for half of its length
(see figure). The outer diameter of the bar is
d2 = 3.0 in. and the diameter of the hole is
d1 = 2.4 in. The total length of the bar is L = 50 in.
At what distance x from the left-hand end of
the bar should a torque T0 be applied so that
the reactive torques at the supports will be equal?
R// x=30.12in

6. Three solid shafts, each of 3/4-in. diameter,
are connected by the gears as shown.
Knowing that G = 11.2 E6 psi, determine
(a) the angle through which end A of shaft
AB rotates,
(b) the angle through which end E
of shaft EF rotates.
R// α_A=24.5° α_E=19.37°