Question

30 in weighs 0.042 lbf in air. Consider the A hydrometer with a stem diameter following: 1) Determine the submerged volume (ft) when the hydrometer floats in water (y = 62.4 lbfift? Calculate the submerged volume (ft) when the hydrometer floats in ethylene glycol (SG = 1.12). Evaluate the height (in.) above the free surface where the 1.0 mark resides when the hydrometer floats in ethylene glycol. 111)

Answer 1

solution : A Hydrometer is having D=0.30 inch and w =0.042 lbf in air. (i) when it floats in water let submerged volume is V . So the F.B.D of Hydrometer will be here mg = 0.042 lbf. bright -mg [Note: here we neglect the buoyancy due to so we write Vm r = B = W B Buoyancy air s = B =

Nm = 0.042 62.4 = 6.73 x 10-4 ft3 ii) In ethylene glyed /2 Swater yol Sa Solycel = so so (W) - Tolycol NIE W 1.12 Swater w 1.12 W = 1.12 Iwater Vwater gly Segung = Vm = 6.01810-4 ft 3 1.12 (ii) glycol water h = How the change in immersed volumes is. av = (- 601 + 6.73)x1074 = 0.72x10-4 743 the height raised by area of stem - 0.72 x 10-4 4.908 7 X 104 = 4.9087 x 10 = 0. 1466.8 ft. - 12x 0. 14 668 inch = 1.76 inch The the 1.0 mark will be almost 1.76 inch above free glycol surface. av A = A xE80251 4 so