A body is executing SHM. When the displacement of the body from the mean position is $4 \mathrm{cm}$ and $5 \mathrm{cm}$, the values of the corresponding velocity of the body are $10 \mathrm{cm} {\mathrm{s}}^{-1}$ and $8 \mathrm{cm} {\mathrm{s}}^{-1}$, respectively. The time period of the body is