A wooden block of mass \( 5 \, \text{kg} \) rests on a soft horizontal floor. When an iron cylinder of mass \( 25 \, \text{kg} \) is placed on the top of the block, the floor yields and the block and the cylinder together go down with an acceleration of \( 0.1 \, \text{m s}^{-2} \). The action force of the system on the floor is equal to: