A metal ball weighs 200 Newton in air. When the ball is submerged in water it weighs 150 Newton. The weight of water displaced by the submerged ball is… A. 50
B. 150
C. 200
D. 100

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.