An astronaut living at a space station is in a constant state of free fall- the only force exerted on her and on the space station is the gravitational force due to the Earth. How can an astronaut determine her mass while on an extended stay in space? One method involves vibrational motion. An astronaut sits on a chair that vibrates horizontally at the end of a spring. A motion detector determines the amplitude of vibration and the speed of the chair as it passes through the equilibrium position. The spring has a 1200 N/m spring constant, the amplitude of vibration is 0.50m, and the speed of the chair as it passes through equilibrium is 2.0m/s. Using these data, find the combined mass of the chair and the astronaut.