The bellows of an adjustable camera can be extended so that the largest distance from the lens to the film is 1.45 times the focal length. If the focal length of the lens is 6.14 cm, what is the distance from the closest object that can be sharply focused on the film

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.