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PROBLEM 18.77 (Continued)
PROBLEM 18.78
For the sheet-metal component of Problem 18.77, determine
(a) the angular velocity of the component 0.6 s after the
couple
M
0
has been applied to it, (b) the magnitude of the
dynamic reactions at A and B at that time.
PROBLEM 18.78 (Continued)
PROBLEM 18.78 (Continued)
PROBLEM 18.79
The blade of an oscillating fan and the rotor of its motor have a total
weight of 300 g and a combined radius of gyration of 75 mm. They are
supported by bearings at A and B, 125 mm apart, and rotate at the rate
11800 rpm.
Determine the dynamic reactions at A and B when the
motor casing has an angular velocity 2(0.6 rad/s) .
j
PROBLEM 18.79 (Continued)
PROBLEM 18.80
The blade of a portable saw and the rotor of its motor have a
total weight of 2.5 lb and a combined radius of gyration of
1.5 in. Knowing that the blade rotates as shown at the rate
11500 rpm,
determine the magnitude and direction of the
couple M that a worker must exert on the handle of the saw to
rotate it with a constant angular velocity 2(2.4 rad/s) .ωj
PROBLEM 18.81
The flywheel of an automobile engine, which is rigidly attached to the crankshaft, is equivalent to a 400-mm-
diameter, 15-mm-thick steel plate. Determine the magnitude of the couple exerted by the flywheel on the
horizontal crankshaft as the automobile travels around an unbanked curve of 200-m radius at a speed of
90 km/h, with the flywheel rotating at 2700 rpm. Assume the automobile to have (a) a rear-wheel drive with
the engine mounted longitudinally, (b) a front-wheel drive with the engine mounted transversely. (Density of
steel 3
7860 kg/m .)
PROBLEM 18.82
Each wheel of an automobile has a mass of 22 kg, a diameter of 575 mm, and a radius of gyration of 225 mm.
The automobile travels around an unbanked curve of radius 150 m at a speed of 95 km/h. Knowing that the
transverse distance between the wheels is 1.5 m, determine the additional normal force exerted by the ground
on each outside wheel due to the motion of the car.
PROBLEM 18.83
The uniform thin 5-lb disk spins at a constant rate 2
6 rad/s
about an axis held by a housing attached to a horizontal rod that
rotates at the constant rate 1
3 rad/s. Determine the couple
which represents the dynamic reaction at the support A.
