|}
==Key Stage 4 Foundation==
===Meaning===
[[Upthrust]] is a [[force]] that acts upwards in a [[fluid]] due to the [[fluid]] being [[Displace|displaced]].
: [[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]].
===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===