When the body is at rest, the extension is \\\\(1.5\\ cm\\\\) while force acting on it is \\\\( mg \\\\)Force when it reaches bottom is \\\\(F_b = \\dfrac{mv^2}{r} + mg \\\\)Now using energy balance between topmost point and bottom most point ,\\\\(\\dfrac{1}{2}mv^2=\\dfrac{1}{2}m(\\sqrt{rg})^2+mgh\\\\) (h is the height difference between the top and bottom point ; \\\\(\\sqrt{gr}\\\\) is critical velocity at topmost point )\\\\( v^2 = rg + 2gh\\\\)or, \\\\( v^2 = rg + 4gr = 5 gr\\\\)So, \\\\(F_b = 6mg \\\\)Using this in: \\\\(\\dfrac{e_2}{e_1} = \\dfrac{F_2}{F_1} \\\\), we get:\\\\(e_2 = 1.5 \ imes 6 = 9.0\\: cm \\\\)