Mercury (rho = 13. 600 kg m^3) is poured into a tall glass. Ethyl alcohol (rho =
ID: 1417870 • Letter: M
Question
Mercury (rho = 13. 600 kg m^3) is poured into a tall glass. Ethyl alcohol (rho = 806 kg/m^3) is poured on the top of mercury until the height of ethyl alcohol itself is 105 cm. The air pressure at the top of ethyl alcohol is 1 atm. What is the absolute pressure at a point 5 10 cm below the ethyl alcohol mercury interlace? A cylinder weighs 20.0 N in air The same cylinder when completely submerged in alcohol weighs 28 7N. the volume of the displaced alcohol is 3.90 times 10^-5 m^3. Calculate a) the density of the cylinder and b) the density of alcohol.Explanation / Answer
(a)Pressure at the mercury - alcohol interface = 1atm + palcohol*gHalcohol
= 101.325 kPa + 806*9.81*1.05 Pa
= 101.325 + 8.302 = 109.627 kPa
(b) Volume of the displaced alcohol = volume of the cylinder
therefore Volume of the cylinder = 3.9*10-5 m3
Weight of the cylinder = 29 N
mass of the cylinder = 29/9.81 = 2.956 kg
Density of the cylinder = mass/volume = 2.956/3.9*10-5 = 75.799*103 kg/m3
Now Buoyancy force = 29 - 28.7 = 0.3 N
Buoyancy force = palcohol*g*V = 0.3
palcohol = 0.3 / (9.81*3.9*10-5) = 784.13 kg/m3