A disc with a mass moment of inertia, Iₘ=10 kg⁻ᵐ² is mounted at the end of 1.0 -meter-long solid square rod,25 mm per side. The torsional natural frequency in rad/s is given by ωₙ = √ kₜ/Iₘ \, where formulas for kₜ are found in text or notes Determine the torsional natural frequency of the system for the rod for three different materials:
(a) steel
(b) aluminum, and
(c) copper.