Imagine a tunnel dug along a diameter of the earth. Show that a particle dropped from one end of the tunnel executes simple harmonic motion. What is the time period of this motion? Assume the earth to be a sphere of uniform mass density (equal to its known average density=5520 kg `m^(-3)`.)G=`6.67xx10^(-11)Nm^(2)kg^(-2)`.Neglect all damping forces.