Solutions (^127)
Since sin cc = VI. — toss a = V1 — (d/2R) 2 , the
velocity of the upper point of "intersection" of the
hoops is
V
VA-
2 V1 —(c//2R) 2
1.25. By hypothesis, the following proportion is
preserved between the lengths 4, / 2 , and / 3 of
segments A °Ai , A 0 A 2, and A 0 A 3 during the mo-
tion:
13 :1 2 :1 3 = 3:5:6.
Therefore, the velocities of points A1, A 2, and A
are to one another as
v Al• • v A,• v A, =3 • 5 6 • ' I
and hence (Fig. 141)
v 5v
v A = 2 V A 2 •
Let us now consider the velocity of the middle
link (A 1 B 2 A 2 C 2 ) at the instant when the angles
of the construction are equal to 90°. In the reference
frame moving at a velocity vAi, the velocity 14 3.
of point B2 is directed at this instant along B 2 A 2.
The velocity of point A 2 is directed along the
horizontal and is given by
uAs = = 3•
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