A 5.0 kg block w ith a speed of 3.0 mis collides w ith a 10 kg block that has a speed of 2.0 mis in the same direction. After the collision, the 5.0 kg block is movingw ith speed of 2.0 mis and 10 kg block is movingw ith speed of 2.5 mis, in the original direction. By how much does the total kinetic energy of the system of two blocks change because of the collision?