\(T =2 \pi \sqrt{\frac{ L }{ g }}\)
When lift is moving upwards \(\Rightarrow\) Pseudo force acts downwards
\(\Rightarrow g _{ eff }= g +\frac{ g }{2}=\frac{3 g }{2}\)
\(\Rightarrow\) New time period
\(T ^{4}=2 \pi \sqrt{\frac{ L }{ g _{ eff }}}=2 \pi \sqrt{\frac{2 L }{3 g }}\)
\(T ^{\prime}=\sqrt{\frac{2}{3}} T\)
$(A)\;y= sin\omega t-cos\omega t$
$(B)\;y=sin^3\omega t$
$(C)\;y=5cos\left( {\frac{{3\pi }}{4} - 3\omega t} \right)$
$(D)\;y=1+\omega t+{\omega ^2}{t^2}$