Size Reduction and Material Handling

Using Kick's law $E = K_K \ln(d_1 / d_2)$, calculate the energy required in $\text{kJ/kg}$ to crush agricultural produce from $d_1 = 20\text{ mm}$ to $d_2 = 5\text{ mm}$ if the Kick's constant is $K_K = 12.5\text{ kJ/kg}$.