This is my problem: A 28 kg. block is connected to an empty 1.00 kg. bucket by a cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.45 and the coefficient of kinetic friction between the table and the block is 0.32. Sand is gradually added to the bucket until the system just begins to move. (a) Calculate the mass of sand added to bucket. (b) Calculate the acceleration of the system. Now, I found this problem pretty vague. I'm assuming the the heavier block is on the table, which makes the most sense. I'm not sure why they gave me both the static and kinetic friction. My problem is I'm not sure how to decide the exact amount of sand to add.