Page 6 of 11 6. A block on a horizontal floor is attached to a horizontal spring that is initially compressed 0.0400 m. The spring has spring constant 840 N/m. The block and spring are released from rest, and the block slides along the floor. If the speed of the block when it has moved a distance of 0.0200 m from its initial position is 0.40 m/s, what is the mass of the block if the coefficient of kinetic friction between the floor and the block is 0.391