Q (3) A closed tank contains 1.5 m of SAE 30 oil (p= 890 kg/m) , 1 m of water, 20 cm of mercury(p= 13568 kg/m), and an air space on top. If Pton = 60 kPa, what

Réponse :

pression ( pressure ) in the air space :

   = 105 hPa ( ≈ 1,52 PSI )

Explications :

■ BONJOUR !

■ "1,5 meter of oil" --> height = 1,5 meter ( ok ? )

■ A closed tank contains 1.5 m of SAE 30 oil (p= 890 kg/m³) , 1 m of water, 20 cm of mercury(p= 13568 kg/m³), and an air space on top. If Pton = 600 hPa, what is the pressure in the air space?

■ prenons un réservoir de surface au sol 1 m²

■ masse d' huile ( oil ) ?

  masse = Volume x 890 kg/m³ = 1,5 m³ x 890 kg/m³ = 1335 kg

■ masse d' eau ( water ) = 1000 kg

■ masse de mercure ?

   0,2 x 1 x 13568 = 2713,6 kg .

■ on aura le réservoir ainsi :

   air --> ( top )

   oil -->

   eau -->

   mercure --> high density

■ Poids ( weight ) TOTAL des liquides :

  (1335+1000+2713,6) x gravité = 5048,6 x 9,8 ≈ 49476 Newton .

■ pression ( pressure ) due aux 3 liquides :

  p = Poids/Surface   ♥

     = 49476 Newton/1 m² = 49476 Pascal ≈ 495 hPa .

■ pression ( pressure ) in the air space :

   600 - 495 = 105 hPa ( ≈ 1,52 PSI ) .

■ use french language please !