A small lake with volume of 160,000 m^3 receives agricultural drainage waters that contain 150 mg / L total dissolved solids (TDS). The drainage waters are the only source of water into the pond and evaporation is the only loss of water from the pond. Fluxes of water due to both evaporation and drainage water are 60,000 m^3 / year (the volume of the water in the lake will not change with time). If the lake is initially filled with water with 100 mg / L TDS, after how many years will the lake no longer be considered to contain freshwater?

An engine, weighing 3000 n, is supported on a pedestal mount. it has been observed that the engine induces vibration into the surrounding area through its pedestal at the maximum operating speed. determine the stiffness of the dynamic vibration absorber spring in (n/m) that will reduce the vibration when mounted on the pedestal. the magnitude of the exciting force is 250 n, and the amplitude of motion of the auxiliary mass is to be limited to 2 mm note: in this question type-in right numbers, no decimals, no fractions, no unit. approximate to right number if needed