An engineering summer student is asked to determine the surface tension of a sample of liquid. She has access to thin wire of various diameters and conducts a series of experiments. The wire is made of a material with a specific weight of s = 75,000 N/m3 . She cuts wires of different diameters into 5 cm long pieces and carefully lowers them onto the surface of the liquid. She finds that a wire with a diameter D = 0.5 mm sinks and that a wire with a diameter of D =0.45 mm stays suspended on the surface