Jack is sitting on a plank of uniform wood of length L that his dad and mom, Jason, Jun, are holding. Jack is sitting 1/4 of the length of the plank of wood away from his father. If the mass of the plank of wood is M, Jack\'s mass is m, and the plank of wood and Jack are in static equilibrium. a. What is the force F 1 provide Jason? b. What is the force F 2 provided by Jun? Solution Suppose Jason is on left side and Jun is on right side to tha Jack. Weights of Jack and plank areare mg and Mg Now, taking moment about Jun\'s end F1 *L = Mg*(L/2) + mg * (3/4)*L So, F1= (2Mg + 3mg)/4 And F2 = mg + Mg - F1 F2=( 2Mg+ mg)/4 .