In order to study the long-term effects of weightlessness, astronauts in space must be weighed (or at least "massed"). one way in which this is done is to seat them in a chair of known mass attached to a spring of known force constant and measure the period of the oscillations of this system. the 35.6 kg chair alone oscillates with a period of 1.30 s, and the period with the astronaut sitting in the chair is 2.23 s. find the force constant of the spring. find the mass of the astronaut.