1. The problem statement, all variables and given/known data A helical spring of stiffness k is cut into two halves and a mass m is connected to the two halves. The natural time period of this system is found to be 0.5 sec. If an identical spring is cut so that one part is one-fourth and the other part is three-fourths of the original length, and the mass m is connected to the two parts, what would be the natural period of the system? 2. Relevant equations 3. The attempt at a solution Attached is the solution. Why is k2 = 4k? I understand the solution up until that point.