Water with pressure of 190 kPa flows down hill through a pipe with a 3.90 cm diameter hose at a speed of 1.2 m/s. It then exits through a smaller pipe m of diameter 1.50 cm which is 5.00 m below the upper pipe.

a. What is the speed of the water exiting at the lower pipe opening?

b. What is the water pressure at the exit of the lower pipe. ?

a)    v₂ = 8,112 m / s , b)   P₂ = 206.8 10³ Pa

Explanation:

This is a fluid mechanics exercise, let's use index 1 for thick pipe and index 2 for thinner pipe

a) with the continuity equation it allows to find the speed of the water  

          v₁ A₁ = v₂ A₂

the area of a circle is

          A₁ = π r₁² = π d₁² / 4

         v₂ = v₁ d₁² / d₂²

let's calculate

         v₂ = 1.2 3.90² / 1.50²

         v₂ = 8,112 m / s

b) We use Bernoulli's equation

         P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂

          P2 = P1 + ½ ρ (v₁² - v₂²) +ρ g (y₁ -y₂)

let's calculate

         P₂ = 190 10³ + ½ 1000 (1.2² - 8.112²) + 1000 9.8 5

         P₂ = 206.8 10³ Pa

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

c because the action was the roller coaster reaches bottom of hill (action) reaction would be blood tends to drain away from head

hope this !