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Work Done

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==Key Stage 3==

===Meaning===

[[Work Done]] is the amount of [[Energy Transfer|energy transferred]] by the action of a [[force]]. ===About Work Done===: [[Work Done]] is measured in [[Joule]]s.: [[Work Done]] can only be calculated for [[object]]s moving in the direction of the [[force]]. If the direction of the [[force]] and the motion of an [[object]] are [[perpendicular]] then no '''work''' is being done on the [[object]] by that [[force]].

===Equation===

Work Done = (Force) x (Distance moved in the direction of the force)

<math> W = F \times d</math>

: Work done is written with a capital W. Force is written with a capital F. Distance is written with a lower case d.

===Example Calculations===

{| border="1" style="border-collapse:collapse"

|-

| style="height:20px; width:200px; text-align:center;" |'''A person lifts a 40N box by a height of 1.2m. Calculate the work done by the person against gravity.'''

| style="height:20px; width:200px; text-align:center;" |'''The brakes on a car apply a force of 10,000N. The car travels a distance of 15m braking. Calculate the work done by the brakes.'''

| style="height:20px; width:200px; text-align:center;" |'''A person carries a 20N box along a horizontal path of 20m.'''

|-

| style="height:20px; width:200px; text-align:left;" |

Force = 40N

Distance moved in the direction of the force = 1.2m

<math> W = 40 \times 1.2</math>

| style="height:20px; width:200px; text-align:left;" |

Force = 10,000N

Distance moved in the direction of the force = 15m

<math> W = 10,000 \times 15</math>

| style="height:20px; width:200px; text-align:left;" |

Force = 40N

Distance moved in the direction of the force = 0m

<math> W = 20 \times 0</math>

No '''work''' has been done because the movement is not in the direction of the [[force]]. The [[weight]] acts downwards but the movement was horizontal.

|}

===Work Done by Deformation===

: When an [[object]] is [[deformation|deformed]], such as a spring being stretched, '''work''' is done to [[Energy Transfer|transfer energy]] into its [[Elastic Potential Energy Store]].

====Work Done on a Spring====

{| class="wikitable"

|-

|[[File:HookesLawSpring.png|center|400px]]

|-

| style="height:20px; width:200px; text-align:left;" |'''Work''' is done to stretch this spring.

|}

The '''work done''' on a [[Coil Spring|spring]] can be found with the following equation

Where:

W = [[Work Done]]

k = [[Spring Constant]]

x = [[Extension]] of the [[object]].

==Key Stage 4==

===Meaning===

[[Work Done]] is the amount of [[Energy Transfer|energy transferred]] by the action of a [[force]].

===About Work Done===

: [[Work Done]] is measured in [[Joule]]s.

====Work Done by a Force====

: [[Work Done]] by a [[force]] can only be calculated for [[object]]s moving in the direction of the [[force]]. If the direction of the [[force]] and the motion of an [[object]] are [[perpendicular]] then no '''work''' is being done on the [[object]] by that [[force]].

====Work Done by Electricity====

: '''Work''' can also be done by an [[Electrical Current|electrical current]] as the [[Electrostatic Field|electrostatic field]] inside a [[wire]] provides a [[force]] to move the [[electron]]s (or [[ion]]s).

===Equation for Work Done by a Force===

'' '''Work Done''' = (Force) x (Distance moved in the direction of the force)''

Where:

W = Work done

F = The [[Force]] applied to the [[object]].

d = The distance moved by the [[object]] in the direction of the [[force]].

===Equation for Work Done by Electricity===

'' '''Work Done''' = (Current) x (Potential Difference) x (time)''

Where:

W = Work done

I = The [[Electrical Current|current]] through the [[Electrical Component|component]]

V = The [[Potential Difference|potential difference]] across the [[Electrical Component|component]].

t = The length of [[time]] that the [[Electrical Current|current]] is flowing.

''NB: You do not need to remember this equation. However you do need to remember the two equations which are combined to make this equation.''

1. <math> P = IV</math>

2. <math> W = Pt</math>

Where:

P = [[Power]]

''Equation 1 is [[Substitute (Maths)|substituted]] into equation 2 to give'' <math> W = IVt</math>.

===Equation for Work Done by Deformation===

Where:

W = [[Work Done]]

k = [[Spring Constant]]

x = [[Extension]] of the [[object]].

===References===

====AQA====

:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Work done, pages 18-21, 99, 170, GCSE Physics; Student Book, Collins, AQA '']

:[https://www.amazon.co.uk/gp/product/1782946403/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946403&linkCode=as2&tag=nrjc-21&linkId=32a0abb60dff015b15b50e9b1d7b4644 ''Work done, pages 32, 33, 135, 136, GCSE Combined Science Trilogy; Physics, CGP, 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 ''Work done, pages 33, 34, 155, 156, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA '']

:[https://www.amazon.co.uk/gp/product/019835939X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=019835939X&linkCode=as2&tag=nrjc-21&linkId=57e96876985fc39b1a3d8a3e3dc238b6 ''Work done, pages 8-9, GCSE Physics; Third Edition, Oxford University Press, AQA '']

====Edexcel====

:~~<math>~~ [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 ''Work done, pages 130, 195, 201, GCSE Physics, Pearson 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 ''Work done; against friction, page 201, GCSE Physics, CGP, 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 ''Work done; by brakes, page 52, GCSE Physics, CGP, 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 ''Work ~~Done~~ done; by charges, pages 224, 242, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp= ~~Force \times Distance<~~1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Work done; by forces, pages 62, 63, 199, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/~~math>~~gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Work done; in stretching, page 325, GCSE Physics, CGP, 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 ''Work done; on gases, page 312, GCSE Physics, CGP, Edexcel '']

====OCR====:[https:~~<math> W~~ //www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie= ~~F \times d</math>~~UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Work done, pages 168. 169, 171, 172, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR '']

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