A) 60 Hz
B) 90 Hz
C) 135 Hz
D) 180 Hz
Correct Answer: B
Solution :
\[d\text{ }=\text{ }30\text{ }mm,\text{ }l\text{ }=\text{ }500\text{ }mm,\text{ }m\text{ }=\text{ }10\text{ }kg,\] \[E=2.1\times {{10}^{11}}Pa\] \[k=\frac{48EI}{{{l}^{3}}}=\frac{48\times 2.1\times {{10}^{11}}\times \pi {{(30\times {{10}^{-\,3}})}^{4}}}{64\times {{(0.5)}^{3}}}\] \[=3206309\text{ }N/m\] \[{{f}_{c}}=\frac{1}{2\pi }\sqrt{\frac{k}{m}}=\frac{1}{2\pi }\sqrt{\frac{3206309}{10}}=90\,Hz\]You need to login to perform this action.
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