Question

A. A 3-kg plastic tank that has a volume of 0.2 m^3 is lled with liquid water. Assuming the density of water is 1000 kg=m^3, determine the weight of the combined system.

b. Is the weight of a system an extensive or intensive property?
c. When analyzing the acceleration of gases as they ow through a nozzle, what would you choose as your system? What type of system is this?
d. Determine the pressure exerted on the surface of a submarine cruising 175 ft below the free surface of the sea. Assume that the atmospheric pressure is 14.7 psia and the speci c gravity of seawater is 1.03. (Consider density of water at 32°F to be 62.4 lbm=ft^3)

Answer 1

The answer is below

Step-by-step explanation:

a) The weight of the combined system is the sum of the weight of the water and the weight of the tank

`m_(water)=V_(tank).\rho_(wtaer)\\\\m_(water)=0.2m^3*1000kg/m^3\\\\m_(water)=200 \ kg\\\\m_(total) = m_(water)+m_(tank)\\\\But\ m_(tank)=3kg,therefore:\\\\m_(total) =200kg+3kg\\\\m_(total) =203\ kg\\\\weight_(total)=m_(total)g\\\\weight_(total)=203kg*9.81m/s^2\\\\weight_(total)=1991.43\ N`

b) Since the weight of a system can be divided into smaller portions, hence weight is an extensive property.

c) When analyzing the acceleration of gases as they flow through a nozzle, the geometry of the nozzle which is an open system can be chosen as our system.

d) Given that:

`\rho_(water)=1000kg/m^3\\\\1kg/m^3=0.062428lb/ft^3\\\\1000kg/m^3=1000kg/m^3*(0.062428lb/ft^3)/(kg/m^3)=62.43lb/ft^3\\ \\\rho=SG*\rho_(water)=1.03*62.43=64.272lb/ft^3\\\\P=P_(atm)+\rho g H\\\\P=14.7\ psia+64.272\ lb/ft^3*32.2\ ft/s^2*175\ ft*(1\ ft^2)/(12^2\ in^2)*(1\ lbf)/(32.2\ lbm.ft/s^2) \\\\P=92.8\ psia`