Usaha dan Energi Pembahasan Soal 1

\begin{equation*}
\begin{split}
EM & = EP_1 + EK_1 \\\\
EM & = m \:.\: g \:.\: h_1 + 0 \\\\
EM & = m \:.\: 10 \:.\: 120 \\\\
EM & = 1200 \: m
\end{split}
\end{equation*}

Energi mekanik (E_M) selalu sama di setiap lintasan.

\begin{equation*}
\begin{split}
EM & = EP_2 + EK_2 \\\\
EM & = \frac{5}{8} EM + EK_2 \\\\
EK_2 & = EM - \frac{5}{8} EM \\\\
EK_2 & = \frac{3}{8} EM
\end{split}
\end{equation*}

\begin{equation*}
\begin{split}
E_{M} & = \frac{1}{2} \:.\: m \:.\: v_2^2 \\\\
\frac{3}{8} \:.\: EM & = \frac{1}{2} \:.\: m \:.\: v_2^2 \\\\
\frac{3}{8} \:.\: 1200 \: m & = \frac{1}{2} \:.\: m \:.\: v_2^2 \\\\
450 \: \cancel {m} & = \frac{1}{2} \:.\: \cancel {m} \:.\: v_2^2 \\\\
900 & = v_2^2 \\\\
30 \text{ m/s} & = v_2
\end{split}
\end{equation*}