A shell of mass 20 kg at rest explodes into two fragments whose...

Total mass of the shell $=20 \mathrm{~kg}$ Ratio of the masses of the fragments $=2: 3$ $\therefore$ Masses of the fragments are 8 kg and 12 kg Now, according to the conservation of momentum $m_1 v_1=m_2 v_2$ $\therefore \quad 8 \times 6=12 \times v$ $v$ (velocity of the larger fragment $)=4 \mathrm{~m} / \mathrm{s}$ Kinetic energy $=\frac{1}{2} m v^2$ $=\frac{1}{2} \times 12 \times(4)^2=96 \mathrm{~J}$