Mary applies a force of 79N to push a box with an acceleration of 0.56 m/s. When she increases the pushing force to 90 N, the box's acceleration changes to 0.83 m/s. There is a constant friction force present between the floor and the box.
A.) What is the mass of the box? (answer in kg)
B.) What is the coefficient of the kinetic friction between the floor and the box?