Two identical 10-kg spheres are attached to the light rigid rod, which rotates in the hori...

Two identical 10-kg spheres are attached to the light rigid rod, which rotates in the horizontal plane centered at pin O . If the spheres are subjected to tangential forces of P = 10 N, and the rod is subjected to a couple moment M = (8t) N • m, where t is in seconds, determine the speed of the spheres at the instant t = 4 s. The system starts from rest. Neglect the size of the spheres.