A28kg block is connected to an empty 1.35kg bucket by a cord running over a frictionless pulley. the coefficient of static friction between the table and the block is .450 and the coefficient of kinetic friction between the block and the table is .320. sand is gradually added to the bucket until the system just begins to move. calculate the mass of the sand added to the bucket

Max. static friction=coefficient of static friction *normal force =28*.45=12.6kgf Sand reqd to be added to the bucket for the system to move =12.6-1.35=11.25kg Kinetic friction=coefficient of kinetic friction*normal force =.32*28=8.96kgf net force acting on the system=force applied -kinetic friction =12.6-8.96=3.64kgf=3.64*9.81 Newtons acceleration of system=net force/mass being moved=Newtons/kg=met/sc^2 =3,64*9.81/12.6=2.834met/sec^2