Mary appiies a force of 76 N to push a box with an acceleration of 049 rnlfsz, when she increases the pushing force to 86 N, the box's acceleration changes to 0'79 mfsz, There is a constant friction force present between the floor and the box. (a) What is the mass of the box in kilograms? 13195 3' Consider appiying Newton's Second Law to each of the pushing forces. kg (b) What is the coefcient of kinetic friction between the floor and the box? 3 589 x What is the reiation between friction force and normal force? Did you apply Newton's Second Law to motion in the veiticai direction