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Difference between revisions of "Upthrust"

(Calculating Upthrust)
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==Key Stage 4 Foundation==
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==Key Stage 4==
 
===Meaning===
 
===Meaning===
 
[[Upthrust]] is a [[force]] that acts upwards in a [[fluid]] due to the [[fluid]] being [[Displace|displaced]].
 
[[Upthrust]] is a [[force]] that acts upwards in a [[fluid]] due to the [[fluid]] being [[Displace|displaced]].
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: [[Upthrust]] is weak in the [[air]] because the [[air]] is not very [[Density|dense]]. For most [[object]]s in [[air]] [[upthrust]] can be ignored because it is so small.
 
: [[Upthrust]] is weak in the [[air]] because the [[air]] is not very [[Density|dense]]. For most [[object]]s in [[air]] [[upthrust]] can be ignored because it is so small.
 
: [[Upthrust]] is caused by the [[pressure]] in a [[fluid]]. [[Pressure]] increases with [[depth]] so the bottom of an [[object]] will experience more [[pressure]] than the top. This difference in [[pressure]] results in a difference between the [[force]] on the bottom and the top, known as [[upthrust]].
 
: [[Upthrust]] is caused by the [[pressure]] in a [[fluid]]. [[Pressure]] increases with [[depth]] so the bottom of an [[object]] will experience more [[pressure]] than the top. This difference in [[pressure]] results in a difference between the [[force]] on the bottom and the top, known as [[upthrust]].
 
 
===Key Stage 4 Higher===
 
===Calculating Upthrust===
 
''NB: You don not need to remember the following equation.''
 
 
Pressure = (Density of the fluid) x (Gravitational Field Strength) x (Depth)
 
 
<math> P = \rho g h</math>
 
 
Where:
 
 
<math> P</math> = [[Pressure]] caused by the [[fluid]].
 
 
<math>\rho</math> = [[Density]] of [[fluid]].
 
 
<math>g</math> = [[Gravitational Field Strength]]
 
 
<math>h</math> = [[Depth]] of the [[object]] in the [[fluid]].
 
 
'' '''Upthrust''' = (Difference in pressure between top and bottom) x (Cross sectional area perpendicular to depth)
 
 
<math> F_u = \Delta P A</math>
 
 
Where:
 
 
<math> F_u</math> = The [[force]] of [[upthrust]].
 
 
<math> \Delta P</math> = [[Pressure]] difference between the top and bottom of the [[object]].
 
 
<math>A</math> = [[Cross Sectional Area|Cross sectional area]] of the [[object]] [[perpendicular]] to the [[height]].
 
 
===Example Calculations===
 
 
{| class="wikitable"
 
|-
 
|[[File:UpthrustCalculation1.png|center|200px]]
 
|[[File:UpthrustCalculation2.png|center|200px]]
 
|[[File:UpthrustCalculation3.png|center|200px]]
 
|-
 
| style="height:20px; width:200px; text-align:center;" |A cube of 1m sides is submersed in [[water]] which has a [[density]] of 1000kg/m3 on [[Earth]] with a [[Gravitational Field Strength|gravitational field strength]] of 9.8N/kg.
 
| style="height:20px; width:200px; text-align:center;" |A cube of 20m sides is submersed in [[water]] which has a [[density]] of 1000kg/m3 on [[Earth]] with a [[Gravitational Field Strength|gravitational field strength]] of 9.8N/kg.
 
| style="height:20px; width:200px; text-align:center;" |A cube of 4m sides is submersed in [[water]] which has a [[density]] of 1000kg/m3 on [[Earth]] with a [[Gravitational Field Strength|gravitational field strength]] of 9.8N/kg.
 
|-
 
| style="height:20px; width:200px; text-align:center;" |'''
 
| style="height:20px; width:200px; text-align:center;" |
 
| style="height:20px; width:200px; text-align:center;" |
 
|}
 
  
 
===Examples===
 
===Examples===

Revision as of 12:08, 11 February 2019

Key Stage 3

Meaning

Upthrust is a force that acts upwards in a fluid due to the fluid being displaced.

About Upthrust

Upthrust is a force so it is measured in Newtons.
The force of upthrust is equal to the weight of fluid that has been displaced by an object.
An object in the water experiences more upthrust than an object in air because water is more dense than air.
Upthrust is weak in the air because the air is not very dense. For most objects in air upthrust can be ignored because it is so small.
Upthrust is caused by the pressure in a fluid. Pressure increases with depth so the bottom of an object will experience more pressure than the top. This difference in pressure results in a difference between the force on the bottom and the top, known as upthrust.

Examples

UpthrustBoat.png
UpthrustSubmarine.png
A boat floats on the water because the weight is balanced by the upthrust. A submarine can change the amount of upthrust in order to rise or sink in the water.

Key Stage 4

Meaning

Upthrust is a force that acts upwards in a fluid due to the fluid being displaced.

About Upthrust

Upthrust is a force so it is measured in Newtons.
The force of upthrust is equal to the weight of fluid that has been displaced by an object.
An object in the water experiences more upthrust than an object in air because water is more dense than air.
Upthrust is weak in the air because the air is not very dense. For most objects in air upthrust can be ignored because it is so small.
Upthrust is caused by the pressure in a fluid. Pressure increases with depth so the bottom of an object will experience more pressure than the top. This difference in pressure results in a difference between the force on the bottom and the top, known as upthrust.

Examples

UpthrustBoat.png
UpthrustSubmarine.png
A boat floats on the water because the weight is balanced by the upthrust. A submarine can change the amount of upthrust in order to rise or sink in the water.