PH03-03 Physics Coming soon
Resultant forces
PH03-03
This lesson is coming soon.
In this lesson
Replace all the forces acting along one straight line with the single resultant force that has exactly the same effect, giving its size and its direction.
What it covers
- The resultant as the SINGLE force that would have exactly the same effect as all the forces acting together
- Adding two or three forces along one straight line: same direction add them, opposite directions subtract
- Choosing a positive direction FIRST and writing it on the diagram, so a negative answer means something instead of being an error
- Giving every resultant a size in newtons AND a direction - never one without the other
- Balanced forces: a resultant of zero, and what that does and does not tell you
- ZERO RESULTANT DOES NOT MEAN NO FORCES - a book on a table, a car at a steady speed, a child sitting still on a swing
- Reading a resultant off a simple picture with two or three arrows on one line
- Saying what the resultant is, without yet saying what it does to the motion
Key words
For: AQA GCSE 8463, Edexcel GCSE 1PH0, OCR GCSE J249
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8463 | 4.5.1.4a | Resultant forces |
| Edexcel GCSE 1PH0 | 9.4 | Draw and use free body force diagrams |
| Edexcel GCSE 1PH0 | 9.5 | Explain examples of the forces acting on an isolated solid object or a system where several forces lead to a resultant force on an object and the special case of balanced forces when the resultant force is zero |
| OCR GCSE J249 | P2.2f | Describe examples of the forces acting on an isolated solid object or system |
| OCR GCSE J249 | P2.2g | Describe, using free body diagrams, examples where two or more forces lead to a resultant force on an object |
| OCR GCSE J249 | P2.2h | Describe, using free body diagrams, examples of the special case where forces balance to produce a resultant force of zero (qualitative only) |
For teachers
This GCSE Physics lesson teaches resultant forces. By the end, students should be able to replace all the forces acting along one straight line with the single resultant force that has exactly the same effect, giving its size and its direction. It works through three worked examples and the mistakes examiners report, and suits Foundation and Higher tier students.