A body of mass m is attached to the lower end of a spring whose upper end is fixed. The spring has negligible mass. When the mass m is slightly…

A body of mass $\displaystyle m$ is attached to the lower end of a spring whose upper end is fixed. The spring has negligible mass. When the mass $\displaystyle m$ is slightly pulled down and released, it oscillates with a time period of $\displaystyle 3$ s. When the mass $\displaystyle m$ is increased by $\displaystyle 1$ kg, the time period of oscillations becomes $\displaystyle 5$ s. The value of $\displaystyle m$ in kg is