Step 1: Understand SHM relation.
In vertical spring SHM, the extreme displacement from mean position is related to total travel. The mass moves \(100 \, \text{cm} = 1 \, \text{m}\) from top extreme to bottom extreme.
Step 2: Relate amplitude.
Total distance between extremes = \(2A\). So:
\[
2A = 1 \Rightarrow A = 0.5 \, \text{m}
\]
Step 3: Use SHM energy relation.
At extreme position:
\[
\omega^2 A = g
\]
So:
\[
\omega^2 = \frac{g}{A}
\]
Step 4: Substitute values.
\[
\omega^2 = \frac{10}{0.5} = 20
\]
\[
\omega = \sqrt{20}
\]
Step 5: Find time period.
\[
T = \frac{2\pi}{\omega} = \frac{2\pi}{\sqrt{20}} = \pi\sqrt{20}
\]
Step 6: Final answer.
\[
\boxed{\pi\sqrt{20}}
\]