Explanation:
Given that \(k=10 \cos ^{2} \omega t\)
\(k = 10\left( {\frac{{1 + \cos (2\omega t)}}{2}} \right) = 5[1 + \cos 2\omega t]\)
\({k_{\max }} = 10\,\,\,\,\,\,\,\,\,\,(\cos (2\omega t) = 1)\)
\({k_{\min {\rm{ }}}} = 0\,\,\,\,\,\,\,\,\,\,\,\,(\cos (2\omega t) = - 1)\)
In S.H.M \(T.{E_{\max }} = K \cdot {E_{\max }} = 10\)