Assume that the earth is a solid sphere of uniform density and a tunnel is dug along its diameter throughout the earth. It is found that when a particle is released in this tunnel, it executes a simple harmonic motion. The mass of the particle is \( 100 \, \text{g} \). The time period of the motion of the particle will be (approximately):
(Take \( g = 10 \, \text{ms}^{-2} \), radius of earth = \( 640 \, \text{km} \))
