Difference between revisions of "Gear"
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===About Gears=== | ===About Gears=== | ||
| − | : The multiplying effect of [[gear]]s can be found by the [[ratio]] of the | + | : The multiplying effect of [[gear]]s can be found by the [[ratio]] of the radii or the number of 'teeth'. |
: A [[gear]] with few teeth turning a [[gear]] with many teeth acts to decrease the [[speed]] and increase the [[moment]]. | : A [[gear]] with few teeth turning a [[gear]] with many teeth acts to decrease the [[speed]] and increase the [[moment]]. | ||
: A [[gear]] with many teeth turning a [[gear]] few teeth acts to increase the [[speed]] and decrease the [[moment]]. | : A [[gear]] with many teeth turning a [[gear]] few teeth acts to increase the [[speed]] and decrease the [[moment]]. | ||
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===Example Calculations=== | ===Example Calculations=== | ||
{| class="wikitable" | {| class="wikitable" | ||
| − | | style="height:20px; width:200px; text-align:center;" |A [[gear]] with | + | | style="height:20px; width:200px; text-align:center;" |A [[gear]] with radius 50mm is turned with a [[moment]] of 10Nm. This [[gear]] used to turn a second [[gear]] with a radius of 20mm. Calculate the [[moment]] of the second [[gear]]. |
| style="height:20px; width:200px; text-align:center;" |A [[gear]] with 45 teeth is turned with a [[moment]] of 25Nm. This [[gear]] used to turn a second [[gear]] with a 63 teeth. Calculate the [[moment]] of the second [[gear]]. | | style="height:20px; width:200px; text-align:center;" |A [[gear]] with 45 teeth is turned with a [[moment]] of 25Nm. This [[gear]] used to turn a second [[gear]] with a 63 teeth. Calculate the [[moment]] of the second [[gear]]. | ||
| style="height:20px; width:200px; text-align:center;" |A [[gear]] with 144 teeth is turned with a [[moment]] of 72Nm. This [[gear]] used to turn a second [[gear]] with 60 teeth. Calculate the [[moment]] of the second [[gear]]. | | style="height:20px; width:200px; text-align:center;" |A [[gear]] with 144 teeth is turned with a [[moment]] of 72Nm. This [[gear]] used to turn a second [[gear]] with 60 teeth. Calculate the [[moment]] of the second [[gear]]. | ||
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<math> M = 30Nm</math> | <math> M = 30Nm</math> | ||
|} | |} | ||
| + | |||
| + | ===References=== | ||
| + | ====AQA==== | ||
| + | |||
| + | :[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Gears, page 133, GCSE Physics, Hodder, 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 ''Gears, page 167, GCSE Physics; The Complete 9-1 Course for AQA, CGP, 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 ''Gears, page 171, GCSE Physics; Student Book, Collins, 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=f0dfb66dafcb0c6e9449e7b1a4ae1ac215 ''Gears, page 57, GCSE Physics; The Revision Guide, 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 ''Gears, pages 122-123, GCSE Physics; Third Edition, Oxford University Press, AQA ''] | ||
| + | |||
| + | ====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 ''Gears, page 137, 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 ''Gears, page 213, GCSE Physics, CGP, Edexcel ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/1782945733/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945733&linkCode=as2&tag=nrjc-21&linkId=2a2dbec9db6bf5766c0458d908fa0a52 ''Gears, page 69, GCSE Physics; The Revision Guide, CGP, Edexcel ''] | ||
| + | |||
| + | ====OCR==== | ||
| + | :[https://www.amazon.co.uk/gp/product/1782945687/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945687&linkCode=as2&tag=nrjc-21&linkId=9a598e52189317a20311d7a632747bc9 ''Gears, page 39, Gateway GCSE Physics; The Revision Guide, CGP, OCR ''] | ||
| + | :[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Gears, pages 87, Gateway GCSE Physics, Oxford, OCR ''] | ||
Latest revision as of 11:38, 11 December 2019
Contents
Key Stage 2
Meaning
Gears are circular disks with 'teeth' that lock together with other gears to change how quickly they spin.
About Gears
- Gears are used in bikes, cars, and any engine which turns.
 |
| The speed can be made bigger by turning the larger gear. The small gear will turn more quickly. |
Key Stage 3
Meaning
Gears are circular disks with 'teeth' that can act to increase the speed or the moment of a force.
About Gears
- A small gear turning a large gear acts to decrease the speed and increase the moment.
- A large gear turning a small gear acts to increase the speed and decrease the moment.
Key Stage 4
Meaning
Gears are circular disks with 'teeth' that can act to increase the speed or the moment of a force.
About Gears
- The multiplying effect of gears can be found by the ratio of the radii or the number of 'teeth'.
- A gear with few teeth turning a gear with many teeth acts to decrease the speed and increase the moment.
- A gear with many teeth turning a gear few teeth acts to increase the speed and decrease the moment.
- The force on one gear is equal in magnitude to the force applied to the other gear.
Example Calculations
| A gear with radius 50mm is turned with a moment of 10Nm. This gear used to turn a second gear with a radius of 20mm. Calculate the moment of the second gear. | A gear with 45 teeth is turned with a moment of 25Nm. This gear used to turn a second gear with a 63 teeth. Calculate the moment of the second gear. | A gear with 144 teeth is turned with a moment of 72Nm. This gear used to turn a second gear with 60 teeth. Calculate the moment of the second gear. |
| 1. State the known quantities
Moment = 10N Radius 1 = 50mm = 0.05m Radius 2 = 20mm = 0.02m |
1. State the known quantities
Moment = 25Nm Teeth Ratio = 45:63 |
1. State the known quantities
Moment = 70Nm Teeth Ratio = 144:60 |
| 2. Substitute the numbers into the equation and solve.
\(M = Fd\) \( 10 = F \times 0.05\) \( F = 200N\) An equal force applies to the second gear. \( M = F \times d\) \( M = 200 \times 0.02\) \( M = 4Nm\) |
2. Substitute the numbers into the equation and solve.
\( M = \frac {25}{45} \times 63\) \( M = 35Nm\) |
2. Substitute the numbers into the equation and solve.
\( M = \frac {72}{144} \times 60\) \( M = 30Nm\) |
References
AQA
- Gears, page 133, GCSE Physics, Hodder, AQA
- Gears, page 167, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Gears, page 171, GCSE Physics; Student Book, Collins, AQA
- Gears, page 57, GCSE Physics; The Revision Guide, CGP, AQA
- Gears, pages 122-123, GCSE Physics; Third Edition, Oxford University Press, AQA
Edexcel
- Gears, page 137, GCSE Physics, Pearson Edexcel
- Gears, page 213, GCSE Physics, CGP, Edexcel
- Gears, page 69, GCSE Physics; The Revision Guide, CGP, Edexcel