Question

physics help please

PHY121 Sample Final problems: thermodynamics, heat, and fluids 10pts 1. A large chemical tank containing acid springs a leak in a seam at the bottom. The air pressure outside the tank is atmospheric(Patm 1,013 x10s N/m2) and the absolute pressure inside the tank at the top is 1.4 x 10s Pa with the hole being 2.7 m below the level of the acid in the tank. What velocity will the acid exit the tank through the hole? Assume the velocity of the acid inside the tank is zero and the density of the acid is 1.03 x 10s kg/m3. 10pts 2. To make sure youz don't tell your story, Rocky ties a 44 N concrete block to your ankles, see? Now knowing what youz do about Physics and how the buoyant force on the block helps you, calculate what force you must exert, swimming with your arms to rise to the top when he tosses you in da river. The concrete block has a volume of 1.7 x 10-3m3. Assume your weight is completely cancelled by your buoyant force and just concentrate on the force you need to lift the block underwater. a) Draw the free-body-diagram for the blockvonoloire isutos ertt ai te b) Write down the net force equation for the block in equilibrium. c) Calculate your lifting force from your net force equation. airb are

Answer 1

1.

Use Bernoulli’s eqn,

P₂+1/2*ρ*v₂² + ρgh₂ = P₁+1/2*ρ*v₁²+ ρgh₁

1/2*ρ*(v₂²- v₁²)=(P₁- P₂)+ ρg(h₁- h₂)

v₂= sqrt[(P₁- P₂)+ ρg(h₁- h₂)]/(1/2*ρ)

Plug values,

v₂= sqrt[(1.4*10^5 – 1.013*10^5)+ 1.03*10^3*9.8(0-(-2.7))]/(1/2*1.03*10^3)

v₂= 0.50 m/s