SHM Earth

If a narrow tunnel is dug between $2$ diametrically opposite points of the Earth, assuming the Earth is a solid sphere of uniform density, then any particle released in this tunnel will exhibit a simple harmonic motion.

Calculate the time period of this motion.

Consider the radius of Earth to be $6371$ $km$ and its mass to be $5.972 \times 10^{24}$ $Kg$ .

Let $G$ = $6.67 \times 10^{-11}$ $m^{3}kg^{-1}s^{-2}$ .

Input the answer to 2 decimal places.