You are aboard the International Space Station and are required to keep track of your mass because of your long stay in the free-fall conditions of deep space. To carry out this task, you hook a 215 -kg cargo box to one end of a stiff spring and hook yourself to the spring's other end. With the spring and box initially at rest relative to you, you push off from the cargo box. Floating inside the cabin, you and the cargo box oscillate with a period of \(2.21 \mathrm{~s}\). You then unhook yourself from the spring and attach in your place a cargo box identical to the one at the other end of the spring. The oscillation period for this two-box system is \(3.13 \mathrm{~s}\). Amazingly, even with squeeze-tube food, you seem to be gaining mass.