The equation of motion for a vibrating system with viscous damping is $$\frac{{{d^2}x}}{{d{t^2}}} + \frac{c}{m} \times \frac{{dx}}{{dt}} + \frac{s}{m} \times x = 0,$$      if the roots of the equation are __________ then the system will be under damped.

A. μ₁ = μsinβ B. μ₁ = μcosβ C. $${\mu _1} = \frac{\mu }{{\sin \beta }}$$ D. $${\mu _1} = \frac{\mu }{{\cos \beta }}$$

A. Self-closed B. Force-closed C. Friction closed D. None of these

A. Sliding B. Turning C. Rolling D. Screw

A. None of the links is fixed B. One of the links is fixed C. Two of the links are fixed D. None of these