Question

A spring of unknown stiffness is cut in to four equal parts and a 100 kg mass is supported on the springs as shown in figure. The natural frequency under the free vibrations is found to be 8 rad/sec. If these oscillations are to be damped critically the coefficient of the damper required is

• A. 400 N-Sec/m
• B. 800 N-Sec/m
• C. 1600 N-sec/m
• D. 3200 N-sec/m

Answer 1

The correct option is C 1600 N-sec/m

$\text{For critical damping,}\xi =1$

$C_c=2{\omega }_{n}m=2\times 8\times 100=1600\text{N-s/m}$