Determine the rate of change of the angular momentum HD of the assembly of Prob. 18.3, as...

Determine the rate of change of the angular momentum HD of the assembly of Prob. 18.3, assuming that at the instant considered the assembly has an angular velocity ω = (12 rad/s)i and an angular acceleration α = −(96 rad/s2)i.

Prob. 18.3

Two uniform rods AB and CE, each of weight 3 lb and length 2 ft, are welded to each other at their midpoints. Knowing that this assembly has an angular velocity of constant magnitude ω = 12 rad/s , determine the magnitude and direction of the angular momentum HD of the assembly about D.

Fig. P18.3