1 The end \(A\) of a \(\operatorname { rod } A B\) of length 1.2 m is freely pivoted at a fixed point. The rod rotates about \(A\) in a vertical plane. Calculate the angular speed of the rod at an instant when \(B\) has speed \(0.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).