5.6

Instructions for Objective 5.6

1.    5.6. Read the objective.  Learn the formula and units.

2.    5.6 Demo.  Read the explanation of the picturre

3.    5.6 Questions.  Forward this e-mail to your blog.  Type your answers under the questions.  (This questions are challenging – don’t give up though!)

4.    5.6 Plenary.  Type your answer under the question.

5.    Answers to steps 3 and 4 will be sent separately.  Don’t look at them until you’ve done the work!

 

5.6

07 October 2011

10:40

·         5.6 recall and use the relationship for pressure difference:

 

        pressure difference = height × density × g

                               ∆p = h × ρ × g

 

 

∆p = pressure of the fluid (N/m² or Pa)

h = height of the fluid (m)

ρ = density of the fluid (kg/m³)

g = gravitational field strength (N/kg)

 

 

5.6 Demo - squirting water column

12 October 2011

07:24

·         The bottom hole squirts water the furthest

·         Because the water at the bottom has the greatest pressure

·         Because in the formula ∆p = h × ρ × g, ρ is constant, g is constant and h is large

·         So ∆p = large

 

 

5.6 Questions

07 October 2011

11:53

Collins, p.107

?

Mr. Baker’s Answer:

∆p = h × ρ × g

250,000 - 100,000 = h x 1,000 x 10

h = 15m

?

Mr. Baker’s Answer:

ρ = 0.42g/cm³ = 420kg/m³

 

∆p = h × ρ × g

∆p = 50 x 420 x 1.4

∆p =29,400Pa or 29kPa

Notes:

ρ_{fresh water} = 1,000kg/m³

g = 10N/kg

1,000mbar = 1 bar = 100,000Pa

 

 

 

5.6 Plenary

12 October 2011

07:23

·         Which diver experiences the greatest pressure?

 

they both experience the same pressure.