A uniform disc of mass 0.5 kg and radius r is projected with velocity 18 m/s at t = 0 s on a rough horizontal surface. It starts off with a purely sliding motion at t = 0 s. After 2s it acquires a purely rolling motion (see figure). The total kinetic energy of the disc after 2s will be ________ J (given, coefficient of friction is 0.3 and g = $10 \mathrm{~m} / \mathrm{s}^2$)