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Fluid Pressure

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===Equation===

''NB: You do not need to remember this equation.''

Pressure = (Density of the Fluid) x (Gravitational Field Strength) x (Depth in the fluid)

Where:

<math> P</math> = [[Pressure]] at that depth.

<math> \rho</math> = [[Density]] of the [[fluid]](This symbol is a 'rho' not a 'p')

<math> g </math> = [[Gravitational Field Strength]]

<math>h</math> = [[Depth]] in the [[fluid]]

===Calculating Pressure in a Fluid===

{| class="wikitable"

| style="height:20px; width:200px; text-align:center;" |A whale dives to a depth of 1300m below sea level. Given the density of [[water]] is 1000kg/m3, calculate the [[pressure]] on the whale due to the water correct to two [[Significant Figures|significant figures]].

| style="height:20px; width:200px; text-align:center;" |Normal atmospheric pressure at sea level is 101kPa. A miner works in a mine shaft 550m below the surface of the Earth. Given the density of the [[Earth's Atmosphere|atmosphere]] at this level is 1.2kg/m3, calculate the [[pressure]] on the miner correct to two [[Significant Figures|significant figures]].

| style="height:20px; width:200px; text-align:center;" |A piece of [[Lithium]] is submersed 4.3cm deep in oil prevent it from oxidising. The oil has a [[density]] of 932kg/m3, calculate the [[pressure]] on the [[Lithium]] due to the oil correct to two [[Significant Figures|significant figures]].

|-

| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''

[[Density]] = 1000kg/m3

[[Gravitational Field Strength]] = 9.8N/kg

[[Depth]] = 1300

| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''

[[Density]] = 1.2kg/m3

[[Gravitational Field Strength]] = 9.8N/kg

[[Depth]] = 550m

| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''

[[Density]] = 932kg/m3

[[Gravitational Field Strength]] = 9.8N/kg

[[Depth]] = 4.3cm = 0.043m

|-

| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''

<math> P = 1000 \times 9.8 \times 1300</math>

<math> P \approx 13000000Pa</math>

| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''

<math> P = 1.2 \times 9.8 \times 550</math>

Since the miner also has normal atmospheric pressure 101kPa is added.

<math> P_{Total} = 6468 + 101000</math>

<math> P_{Total} = 107468Pa</math>

<math> P_{Total} \approx 110000Pa</math>

| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''

<math> P = 932 \times 9.8 \times 0.043</math>

<math> P \approx 390Pa</math>

|}

===References===

====AQA====

:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Fluid pressure, pages 169-171, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']

:[https://www.amazon.co.uk/gp/product/178294558X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294558X&linkCode=as2&tag=nrjc-21&linkId=f0dfb66dafcb0c6e9449e7b1a4ae1ac175 ''Fluid pressure, pages 58, 59, GCSE Physics; The Revision Guide, CGP, AQA '']

====Edexcel====

:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Fluid pressure, pages 318, 319, GCSE Physics, CGP, Edexcel '']

:[https://www.amazon.co.uk/gp/product/1292120223/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120223&linkCode=as2&tag=nrjc-21&linkId=068ecf40278c32406a7f1c6e66751417 ''Fluids and pressure, pages 202-203, GCSE Physics, Pearson Edexcel '']

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