Question

Time period of a simple pendulum in a stationary lift is ‘T’. If the lift accelerates with $\frac{g}{6}$ vertically upwards then the time period will be (Where g = acceleration due to gravity)

• A. $\sqrt{\frac{6}{5}}T$
• B. $\sqrt{\frac{5}{6}}T$
• C. $\sqrt{\frac{6}{7}}T$
• D. $\sqrt{\frac{7}{6}}T$

Answer 1

Answer: (C)

$\sqrt{\frac{6}{7}}T$

Answer 2

$T' = 2\pi \sqrt{\frac{I}{g_{\text{eff}}}}$

$T' = 2\pi \sqrt{\frac{I}{g + \frac{g}{6}}} = 2\pi \sqrt{\frac{6I}{7g}}$

$T' = \sqrt{\frac{6}{7}}T$
So,the correct option is C