1. The problem statement, all variables and given/known data A mass hangs from the ceiling of a box by an ideal spring. With the box held fixed, the mass is given an initial velocity and oscillates with purely vertical motion. When the mass reaches the lowest point of its motion, the box is released and allowed to fall. To an observer inside the box, which of the following quantities does not change when the box is released? Ignore air resistance. (A) The amplitude of the oscillation (B) The period of the oscillation <- CORRECT (C) The maximum speed reached by the mass (D) The height at which the mass reaches its maximum speed (E) The maximum height reached by the mass No variables; this is a conceptual problem 2. Relevant equations A_k = -kx/m A_g = mg Period = 1/2*pi * sqrt(m/k) 3. The attempt at a solution I tried to use the two accelerations and set them equal and see what happens: -kx/m = mg g = -kx/m^2 I am confused, I have never seen such a problem, and I don't know what to do. Can someone lead me in the right direction?