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EEJ MAIN Physics QUESTION #7076
Question 1
A simple pendulum has a time period $T$ when measured in a stationary elevator. If the elevator begins to accelerate upwards at a rate of $g/2$, what is the new time period of the pendulum?
  • $\sqrt{\frac{2}{3}}T$✔️
  • $\sqrt{3}T$
  • $\sqrt{\frac{3}{2}}T$
  • $\frac{T}{\sqrt{3}}$
Correct Answer Explanation
The effective gravity $g_{eff}$ in an upward accelerating lift is $g + a = g + g/2 = 3g/2$. Since the time period $T \propto \frac{1}{\sqrt{g}}$, the new period $T' = T \sqrt{\frac{g}{3g/2}} = T \sqrt{\frac{2}{3}}$.