\textbf{167.} The displacement–time graph of an oscillator with mass 50 grams is shown below. The mechanical energy of the oscillator is how many joules? $(\pi^2 = 10)$
\textit{[Figure: x(cm) vs t(s) graph; amplitude 4 cm, $t_1 = \dfrac{2}{15}$ s marked, minimum value $-4$ cm shown.]}
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(1) $\dfrac{1}{250}$ \hspace{1.5cm} (2) $\dfrac{1}{25}$ \hspace{1.5cm} (3) $\dfrac{2}{5}$ \hspace{1.5cm} (4) $\dfrac{1}{50}$
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