The planar four-bar mechanism shown below has a driving crank O1A that turns about O1 at a constant rate of (theta- dot) θ. = 10 rad/s CCW. The links O1A and O2B are balanced and have a mass moments of inertia about their center of mass of Iz = 0.02 kgm2 . The link ABC has a center of mass located at point G, has a mass of m = 2 kg, and has a mass moment of inertia of Iz = 0.1 kgm2 about G.
The geometry of the mechanism is as follows:
O1A = 6 cm, AB = 18 cm, O1O2 = 18 cm
AG = 12 cm, AC = 24 cm, O2B = 6 cm
At the instant shown, the mechanism has the following angles, angular velocities and angular accelerations:
Ignoring the effects of friction and gravity, determine the following:
a) the D'Alembert force set corresponding to each of the three links; and,
b) the external torque required on O1A that must be applied to drive the mechanism at the given instant and to counteract the force FC = -30j N.