Three identical 8.80kg masses are hung by three identical springs, as shown in the figure. Each spring has a force constant of 8.20kN/m and was 13.0cm long before any masses were attached to it. How long is each spring (bottom, middle, lower) when hanging as shown?
(Hint: First isolate only the bottom mass. Then treat the bottom two masses as a system. Finally, treat all three masses as a system.)