Difference between revisions of "Upthrust"
| Line 5: | Line 5: | ||
===About Upthrust=== | ===About Upthrust=== | ||
: [[Upthrust]] is a [[force]] so it is [[Measure|measured]] in [[Newton]]s. | : [[Upthrust]] is a [[force]] so it is [[Measure|measured]] in [[Newton]]s. | ||
| − | : The [[force]] of [[upthrust]] is equal to the [[weight]] of [[fluid]] that has been [[Displace|displaced]]. | + | : The [[force]] of [[upthrust]] is equal to the [[weight]] of [[fluid]] that has been [[Displace|displaced]] by an [[object]]. |
| − | : An [[object]] in the [[water]] experiences | + | : An [[object]] in the [[water]] experiences more [[upthrust]] than an [[object]] in [[air]] because [[water]] is more [[Density|dense]] than [[air]]. |
: [[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]]. | ||
| + | ===Examples=== | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | |[[File:UpthrustBoat.png|center|250px]] | ||
| + | |[[File:UpthrustSubmarine.png|center|300px]] | ||
| + | |- | ||
| + | | style="height:20px; width:300px; text-align:center;" |A boat floats on the water because the [[weight]] is balanced by the [[upthrust]]. | ||
| + | | style="height:20px; width:300px; text-align:center;" |A submarine can change the amount of [[upthrust]] in order to rise or sink in the [[water]]. | ||
| + | |} | ||
| + | |||
| + | ==Key Stage 4 Foundation== | ||
| + | ===Meaning=== | ||
| + | [[Upthrust]] is a [[force]] that acts upwards in a [[fluid]] due to the [[fluid]] being [[Displace|displaced]]. | ||
| + | |||
| + | ===About Upthrust=== | ||
| + | : [[Upthrust]] is a [[force]] so it is [[Measure|measured]] in [[Newton]]s. | ||
| + | : The [[force]] of [[upthrust]] is equal to the [[weight]] of [[fluid]] that has been [[Displace|displaced]] by an [[object]]. | ||
| + | : An [[object]] in the [[water]] experiences more [[upthrust]] than an [[object]] in [[air]] because [[water]] is more [[Density|dense]] than [[air]]. | ||
| + | : [[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 this equation.'' | ||
| + | |||
| + | Upthrust = (Density of the fluid) x (Gravitational Field Strength) x (Object Height) x (Cross sectional area perpendicular to the height) | ||
| + | |||
| + | <math> F_U = \rho g h A</math> | ||
| + | |||
| + | Where: | ||
| + | |||
| + | <math> F_U</math> = [[Force]] of [[upthrust]]. | ||
| + | |||
| + | <math>\rho</math> = [[Density]] of [[fluid]]. | ||
| + | |||
| + | <math>g</math> = [[Gravitational Field Strength]] | ||
| + | |||
| + | <math>h</math> = [[Height]] of [[object]] from top to bottom. | ||
| + | |||
| + | <math>A</math> = [[Cross Sectional Area|Cross sectional area]] of the [[object]] [[perpendicular]] to the [[height]]. | ||
| + | |||
| + | ===Example Calculations=== | ||
| + | |||
| + | |||
===Examples=== | ===Examples=== | ||
{| class="wikitable" | {| class="wikitable" | ||
Revision as of 11:00, 11 February 2019
Contents
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
 |
 |
| 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 Foundation
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.
Key Stage 4 Higher
Calculating Upthrust
NB: You don not need to remember this equation.
Upthrust = (Density of the fluid) x (Gravitational Field Strength) x (Object Height) x (Cross sectional area perpendicular to the height)
\( F_U = \rho g h A\)
Where\[ F_U\] = Force of upthrust.
\(g\) = Gravitational Field Strength
\(h\) = Height of object from top to bottom.
\(A\) = Cross sectional area of the object perpendicular to the height.
Example Calculations
Examples
|
|
| 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. |