$$\begin{array}{rl}& E{M}_{(1)}=E{M}_{(2)}\\ \\ & E{P}_{(1)}+E{K}_{(1)}=E{P}_{(2)}+E{K}_{(2)}\\ \\ & E{P}_{(1)}+E{K}_{\text{translasi }(1)}+E{K}_{\text{rotasi }(1)}=E{P}_{(2)}+E{K}_{\text{translasi }(2)}+E{K}_{\text{rotasi }(2)}\\ \\ & m.g.h_1+\frac{1}{2}.m.v_1^2+\frac{1}{2}.I.{\omega }_1^2=m.g.h_2+\frac{1}{2}.m.v_2^2+\frac{1}{2}.I.{\omega }_2^2\end{array}$$

Perlu diingat juga:

Momen inersia

(1)   silinder pejal = $\frac{1}{2}m{R}^2$

(2)   bola pejal = $\frac{2}{5}m{R}^2$

Hubungan antara $v$ dan $\omega$

$v=\omega .R$