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Free Body Diagram

Key Stage 4

Meaning

A free body diagram is a type of diagram which all the forces affecting an object using arrows to represent the force vectors.

About Free Body Diagram

Free body diagrams show the different forces acting on an object.
The forces are represented by arrows that indication the magnitude of the force with by the length of the arrow and the direction of the force by the direction of the arrow.
The object is usually drawn in a simplistic way as its shape is not often important to the forces that are acting on the object.
Free body diagrams include a label which either names the force or states its magnitude.

Examples

A submarine travelling to the left. A plane flying to the right. A car driving to the right.
SubmarineForces.png
PlaneForces.png
CarForces.png
A = Water Resistance
B = Weight
C = Thrust
D = Upthrust
A = Lift
B = Thrust
C = Weight
D = Air Resistance
A = Normal Contact Force
B = Driving Force
C = Weight
D = Friction
E = Air Resistance
FreeBodyDiagram1.png
FreeBodyDiagram2.png
FreeBodyDiagram3.png
FreeBodyDiagram4.png
This diagram shows an object with a vector force of 5N magnitude directed horizontally to the right. This diagram shows an object with 2 forces of 5N magnitude in opposite directions, vertically. This diagram shows an object with 2 forces. One of 5N magnitude directed horizontally to the right, the other 3.5N directed vertically down. This diagram shows an object with 4 forces with pairs acting in opposing directions. The resultant force here is 1N horizontally to the right.

References

AQA

Free body diagrams, page 122, GCSE Physics, Hodder, AQA
Free body diagrams, page 53, GCSE Physics; The Revision Guide, CGP, AQA
Free body diagrams, pages 131, 132, GCSE Combined Science Trilogy; Physics, CGP, AQA
Free body diagrams, pages 151, 152, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
Free body diagrams, pages 21, GCSE Combined Science Trilogy 2, Hodder, AQA
Free-body diagram, pages 156, 162, GCSE Physics; Student Book, Collins, AQA
Free-body force diagrams, page 119, GCSE Physics; Third Edition, Oxford University Press, AQA

Edexcel

Free body force diagram, page 134, GCSE Physics, Pearson Edexcel
Free body force diagram, page 376, GCSE Combined Science, Pearson Edexcel
Free body force diagrams, pages 207-209, GCSE Physics, CGP, Edexcel

OCR

Free body diagrams, pages 64-65, Gateway GCSE Physics, Oxford, OCR
Free body force diagrams, page 26, Gateway GCSE Physics; The Revision Guide, CGP, OCR
Free body forces diagrams, page 163, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR