The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft, and I = Mass moment of inertia of the disc attached at the end of a shaft)

• A. <img src="/_files/images/mechanical-engineering/theory-of-machines/518-508-1.png">
• B. 2
• C. <span class="root"><i>qI</i></span>
• D. <img src="/_files/images/mechanical-engineering/theory-of-machines/518-508-2.png">
• E. <img src="/_files/images/mechanical-engineering/theory-of-machines/518-508-3.png">