PROBLEM 15.59
The test rig shown was developed to perform fatigue testing
on fitness trampolines. A motor drives the 9–in radius
flywheel AB, which is pinned at its center point A, in a
counterclockwise direction. The flywheel is attached to slider
CD by the 18–in connecting rod BC. Knowing that the “feet”
at D should hit the trampoline twice every second, at the
instant when
θ
= 30°, determine (a) the angular velocity of the
connecting rod BC, (b) the velocity of D, (c) the velocity of
midpoint CB.
PROBLEM 15.60
In the eccentric shown, a disk of 2–in.–radius revolves about shaft O
that is located 0.5 in. from the center A of the disk. The distance
between the center A of the disk and the pin at B is 8 in. Knowing that
the angular velocity of the disk is 900 rpm clockwise, determine the
velocity of the block when
30 .
θ
= °
PROBLEM 15.61
In the engine system shown,
160 mm
l=
and
60 mm.b=
Knowing that the crank
AB rotates with a constant angular velocity of 1000 rpm clockwise, determine the
velocity of the piston P and the angular velocity of the connecting rod when
(a)
0,
θ
=
(b)
90 .
θ
= °
PROBLEM 15.62
In the engine system shown
160 mml=
and b
60 mm.=
Knowing that crank AB
rotates with a constant angular velocity of 1000 rpm clockwise, determine the
velocity of the piston P and the angular velocity of the connecting rod when
60 .
θ
= °
PROBLEM 15.62 (Continued)
/
sin30
cos
6.2832sin30
cos18.95
3.3216 m/s
B
DB
v
v
β
°
=
°
=
/3.3216
0.16
DB
BD
v
l
ω
= =
20.8 rad/s
BD
ω
=
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PROBLEM 15.63
Knowing that at the instant shown the angular velocity of rod AB
is 15 rad/s clockwise, determine (a) the angular velocity of rod
BD, (b) the velocity of the midpoint of rod BD.
PROBLEM 15.64
In the position shown, bar AB has an angular velocity of 4 rad/s clockwise.
Determine the angular velocity of bars BD and DE.
PROBLEM 15.65
Linkage DBEF is part of a windshield
wiper mechanism, where points O, F and D
are fixed pinned connections. At the
position shown,
θ
= 60° and link EB is
horizontal. Knowing that link EF has a
counterclockwise angular velocity of
4 rad/s at the instant shown, determine the
angular velocity of links EB and DB.
PROBLEM 15.66
Robert’s linkage is named after Richard Robert (1789–1864) and can be used
to draw a close approximation to a straight line by locating a pen at Point F.
The distance AB is the same as BF, DF and DE. Knowing that the angular
velocity of bar AB is 5 rad/s clockwise in the position shown, determine
(a) the angular velocity of bar DE, (b) the velocity of Point F.
PROBLEM 15.66 (Continued)
(b) Velocity of Point F.
/
3 135
FB
i= −vj
//
F B FB B BD FB
ω
===+×
v v v v kr