# The mechanism produces intermittent motion of link AB. If the

```The mechanism produces intermittent motion of link AB. If the sprocket S is
turning with an angular velocity of Ws = 6 rad/s, determine the angular velocity
of link AB at this instant. The sprocket S is mounted on a shaft which is
separated from a collinear shaft attached to AB at A. The pin at C is attached to
Solution:
Kinematic Diagram: Since link AB is rotating about the fixed point A,
then VB is always directed perpendicular to link AB its magnitude is
VB =
ω AB rAB =0.2 ω AB . At the instant shown . Vs is directed at an angle 60&deg;
with the horizontal. Since point C is attached to chain , at the instant shown ,it
moves vertically with a speed of Vc = WSrS = 6(0.175) = 1.05m/s
Instantaneous center : The instantaneous center of zero velocity of link BC at the
instant shown is located at the intersection point of extended lines drawn
perpendicular from vB and vC . Using law of sines , we have
rB/rC
Sin105&deg;
=
0.15
sin 30&deg;
rB/rC = 0.2898 m
rC/rC
Sin45&deg;
=
0.15
sin 30&deg;
rC/rC = 0.2121 m
The angular velocity of bar BC is given by
ω BC =
vC
1.05
=
rC / rC
0.2121