Topic: Mechanical Vibrations
A mass of 10 kg is attached to the end of a spring with a stiffness $0.49~N/mm$. The critical damping coefficient of this system is
- A. 14
- B. 70
- C. 140
- D. 700
Answer: C. 140
Explanation: Mass $m = 10~kg$.
Stiffness $k = 0.49~N/mm = 0.49 \times 1000~N/m = 490~N/m$.
The critical damping coefficient is given by $c_c = 2\sqrt{km}$.
$c_c = 2\sqrt{490 \times 10} = 2\sqrt{4900} = 2 \times 70 = 140~Ns/m$.