A box of mass 4.2 kg is pushed up an incline at a constant speed where there is a kinetic friction force of 12 N. Let the length of the incline be 4.0 meters long and the height be 2.0 meters high. Find the simple machine efficiency of this inclined plane by finding the work to push the block up the entire length and the work to lift the block directly up 2.0 meters.