Rotational Kinematics

 
 
The ABCD rod shown rotates on two spherical joints in A and D, in a clockwise direction when viewed from the point of view A. The angular speed of the bar at the instant considered is equal to 12 rad/s, and decreases at the rate of 3 rad/s2. Find:
a) The angular velocity, in rad/s;
b) The angular acceleration, in rad/s2;
c) The velocity of point B, in em m/s;
d) The acceleration of point B, in m/s2.

ABCD rod, AB = 28 centimeters, BC = 18 centimeters and CD = 12 centimeters, rotating around the diagonal AD clockwise when viewed from A.