Question

As shown in the figure, a mass of 100 kg is held between two springs. The natural frequency of vibration of the system in cycle/s, is

• A. $\frac{1}{2\pi }$
• B. $\frac{5}{\pi }$
• C. $\frac{10}{\pi }$
• D. $\frac{20}{\pi }$

Answer 1

The correct option is C $\frac{10}{\pi }$

Springs are in parallel arrangement,

$k_{eq}=k_1+k_2=20+20=40\text{kN/m}$

$\text{Natural frequency}=\frac{1}{2\pi }\sqrt{\frac{40\times {10}^3}{100}}=\frac{10}{\pi }$