8. A worker chooses an unusual way to pull two boxes across a factory floor. The worker pulls one tow rope, which she has tied to the front of Box A. A second tow rope connects the back of Box A to the front of Box B. Both ropes are taut, horizontal, and of negligible mass; the floor is horizontal; and the worker and both boxes move to the right at constant velocity v=1.5m/s. The boxes slide across the floor, but the worker's shoes do not slip as she walks. The coefficient of static friction between the worker's shoes and the floor is s=0.50, while the coefficient of kinetic friction between each box and the floor is k=0.25. (h) Suppose that all of the details of this problem stay unchanged, but the boxes are made more massive. (The worker's mass is unchanged, and the friction coefficients are unchanged.) What is the largest combined mass, mA+mB, for the two boxes that the worker could pull, at constant velocity, before her shoes begin to lose their grip on the floor