The 75-kg man and 40-kg boy sit on the horizontal seesaw, which has negligible mass. At...

The 75-kg man and 40-kg boy sit on the horizontal seesaw, which has negligible mass. At the instant the man lifts his feet from the ground, determine their accelerations if each sits upright, i.e., they do not rotate. The centers of mass of the man and boy are at respectively.