Difference between revisions of "Balanced Forces"
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|[[File:BalancedForces3.png|center|200px]] | |[[File:BalancedForces3.png|center|200px]] | ||
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− | | style="height:20px; width:200px; text-align:center;" |The 7[[N]] up is '''balanced''' by the 7[[N]] down. | + | | style="height:20px; width:200px; text-align:center;" |The 7[[Newton|N]] up is '''balanced''' by the 7[[Newton|N]] down. |
− | | style="height:20px; width:200px; text-align:center;" |The 4[[N]] left is '''balanced''' by the 4[[N]] right. | + | | style="height:20px; width:200px; text-align:center;" |The 4[[Newton|N]] left is '''balanced''' by the 4[[Newton|N]] right. |
− | | style="height:20px; width:200px; text-align:center;" |The 6[[N]] up is '''balanced''' by the 6[[N]] down and the 5[[N]] left is '''balanced''' by the 5[[N]] right. | + | | style="height:20px; width:200px; text-align:center;" |The 6[[Newton|N]] up is '''balanced''' by the 6[[Newton|N]] down and the 5[[Newton|N]] left is '''balanced''' by the 5[[Newton|N]] right. |
|} | |} | ||
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===About Balanced Forces=== | ===About Balanced Forces=== | ||
: When [[force]]s on an [[object]] are '''balanced''' there is no [[acceleration]] (change speed or direction). | : When [[force]]s on an [[object]] are '''balanced''' there is no [[acceleration]] (change speed or direction). | ||
− | : '''Balanced forces''' are related to [[Newton's First Law]] of | + | : '''Balanced forces''' are related to [[Newton's First Law]] of motion: |
− | :: An [[object]] in motion will tend to stay in motion and an [[object]] at [[rest]] will tend to stay at [[rest]] unless an [[Unbalanced Forces|unbalanced force]] acts upon it. | + | :: An [[object]] in motion will tend to stay in motion in a straight line and an [[object]] at [[rest]] will tend to stay at [[rest]] unless an [[Unbalanced Forces|unbalanced force]] acts upon it. |
: If the [[Resultant Force|resultant force]] on an [[object]] is zero, then the [[force]]s are '''balanced'''. | : If the [[Resultant Force|resultant force]] on an [[object]] is zero, then the [[force]]s are '''balanced'''. | ||
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{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
− | |[[File:BalancedForces4.png|center| | + | |[[File:BalancedForces4.png|center|200px]] |
|[[File:BalancedForces5.png|center|200px]] | |[[File:BalancedForces5.png|center|200px]] | ||
|[[File:BalancedForces6.png|center|200px]] | |[[File:BalancedForces6.png|center|200px]] | ||
|- | |- | ||
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
+ | <math>F_R = F_{up} - F_{down}</math> | ||
+ | |||
+ | <math>F_R = 3 - 3</math> | ||
+ | |||
+ | <math>F_R = 0N</math> | ||
+ | |||
+ | The [[force]]s are '''balanced'''. | ||
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
+ | <math>F_R = F_{right} - F_{left}</math> | ||
+ | |||
+ | <math>F_R = 80 - 80</math> | ||
+ | |||
+ | <math>F_R = 0N</math> | ||
+ | |||
+ | The [[force]]s are '''balanced'''. | ||
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
+ | <math>F_{Horiztonal} = F_{right} - F_{left}</math> | ||
+ | |||
+ | <math>F_{Horiztonal} = 40 - 40</math> | ||
+ | |||
+ | <math>F_{Horiztonal} = 0N</math> | ||
+ | |||
+ | <math>F_{Vertical} = F_{up} - F_{down}</math> | ||
+ | |||
+ | <math>F_{Vertical} = 38 - 38</math> | ||
+ | |||
+ | <math>F_{Vertical} = 0N</math> | ||
+ | |||
+ | The [[force]]s are '''balanced'''. | ||
|} | |} | ||
+ | |||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | |[[File:BalancedForces7.png|center|600px]] | ||
+ | |- | ||
+ | | style="height:20px; width:200px; text-align:center;" | | ||
+ | Whether these [[force]]s are '''balanced''' can be found by [[Resolving Forces|resolving]] the blue [[force]] [[vector]]s into the [[horizontal]]. See [[Resolving Forces]]. | ||
+ | |||
+ | <math>F_{right} = 50\cos37 + 50\cos37</math> | ||
+ | |||
+ | <math>F_{right} = 79.86N</math> | ||
+ | |||
+ | Since the [[angle]] in the question is given to two [[Significant Figures|significant figures]] the answer should also be quoted to two [[Significant Figures|significant figures]]. | ||
+ | |||
+ | <math>F_{right} \approx 80N</math> | ||
+ | |||
+ | <math>F_R = F_{right} - F_{left}</math> | ||
+ | |||
+ | <math>F_R = 80 - 80</math> | ||
+ | |||
+ | <math>F_R = 0N</math> | ||
+ | |} | ||
+ | |||
+ | ===References=== | ||
+ | ====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 ''Balanced forces, pages 114-133, GCSE Physics; Third Edition, Oxford University Press, 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 ''Balanced forces, pages 133, 170, 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 ''Balanced forces, pages 153, 166, 202, 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 ''Balanced forces, pages 154-6, GCSE Physics; Student Book, Collins, 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 ''Balanced forces, page 13, GCSE Physics, Pearson Edexcel ''] | ||
+ | :[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Balanced forces, page 297, GCSE Combined Science, Pearson Edexcel ''] |
Latest revision as of 14:13, 2 November 2019
Contents
Key Stage 3
Meaning
Balanced Forces are forces that are the same strength but acting in opposite directions.
About Balanced Forces
The 7N up is balanced by the 7N down. | The 4N left is balanced by the 4N right. | The 6N up is balanced by the 6N down and the 5N left is balanced by the 5N right. |
Key Stage 4
Meaning
Balanced forces are force vectors which add together to make 0N resultant force.
About Balanced Forces
- When forces on an object are balanced there is no acceleration (change speed or direction).
- Balanced forces are related to Newton's First Law of motion:
- An object in motion will tend to stay in motion in a straight line and an object at rest will tend to stay at rest unless an unbalanced force acts upon it.
- If the resultant force on an object is zero, then the forces are balanced.
Examples
\(F_R = F_{up} - F_{down}\) \(F_R = 3 - 3\) \(F_R = 0N\) The forces are balanced. |
\(F_R = F_{right} - F_{left}\) \(F_R = 80 - 80\) \(F_R = 0N\) The forces are balanced. |
\(F_{Horiztonal} = F_{right} - F_{left}\) \(F_{Horiztonal} = 40 - 40\) \(F_{Horiztonal} = 0N\) \(F_{Vertical} = F_{up} - F_{down}\) \(F_{Vertical} = 38 - 38\) \(F_{Vertical} = 0N\) The forces are balanced. |
Whether these forces are balanced can be found by resolving the blue force vectors into the horizontal. See Resolving Forces. \(F_{right} = 50\cos37 + 50\cos37\) \(F_{right} = 79.86N\) Since the angle in the question is given to two significant figures the answer should also be quoted to two significant figures. \(F_{right} \approx 80N\) \(F_R = F_{right} - F_{left}\) \(F_R = 80 - 80\) \(F_R = 0N\) |
References
AQA
- Balanced forces, pages 114-133, GCSE Physics; Third Edition, Oxford University Press, AQA
- Balanced forces, pages 133, 170, GCSE Combined Science Trilogy; Physics, CGP, AQA
- Balanced forces, pages 153, 166, 202, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Balanced forces, pages 154-6, GCSE Physics; Student Book, Collins, AQA