A 28.0-kg block is resting on a flat horizontal table. on top of this block is resting a 18.0-kg block, to which a horizontal spring is attached, as the drawing illustrates. the spring constant of the

A 28.0-kg block is resting on a flat horizontal table. on top of this block is resting a 18.0-kg block, to which a horizontal spring is attached, as the drawing illustrates. the spring constant of the spring is 345 n/m. the coefficient of kinetic friction between the lower block and the table is 0.480, and the coefficient of static friction between the two blocks is 0.750. a horizontal force is applied to the lower block as shown. this force is increasing in such a way as to keep the blocks moving at a constant speed.