Consider the arrangement shown. Table top is rough and coefficient of friction between table top and block 2m is μ. Pulley and string are ideal. Minimum value of μ at table top to keep system at equilibrium, is

Two pans of a balance are 24.1 cm apart. the fulcrum of the balance has been shifted 1.33 cm away from the center by a dishonest shopkeeper. by what percentage is the true weight of the goods being marked up by the shopkeeper? assume the balance has negligible mass. answer in units of %.