A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin)

• A. (1/2). I ω ωP
• B. Iω²
• C. I ω ωP
• D. (1/2).Iω²

Answer: (C)