Vectors and transformation geometry · Vecteurs et géométrie des transformations
| English | Français |
|---|---|
| resultant/rɪˈzʌltənt/ | résultante |
Why is displacement shorter than the walk?
- Walking 4 m east and 3 m north gives a displacement of 5 m, even though the travelled distance is 7 m.
- This lesson studies resultant 合向量: The vector sum representing the combined displacement or force.
Choose the mathematical structure
- Add corresponding vector components and subtract position vectors to find a displacement. A translation moves every point by the same vector; a scalar multiple changes length and possibly direction.
- State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Which description correctly defines resultant? · Laquelle des descriptions définit correctement le vecteur résultant ?
The vector sum representing the combined displacement or force. · La somme vectorielle représentant le déplacement ou la force combinés.
Work through a checked case
- Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
With a=(4,1) and b=(1,3), a+b=(5,4). From A=(1,2) to B=(5,5), displacement AB=(4,3). Its magnitude is √(4²+3²)=5.
Vectors and transformation geometry · Vecteurs et géométrie des transformations
Add corresponding vector components and subtract position vectors to find a displacement · Additionner les composantes vectorielles correspondantes et soustraire les vecteurs de position pour trouver un vecteur déplacement.
Compare the model with the worked case and explain one change. · Compare le modèle avec l'exemple résolu et explique un changement.
Find the x-component of (4,1)+(1,3). · Trouvez la composante x de (4,1)+(1,3).
Add the x-components: 4+1=5. · Ajoutez les composantes x : 4+1=5.
Test a tempting shortcut
- The order of subtraction matters: BA=-AB. Proving parallelism needs a scalar-multiple relation; a sketch alone is insufficient. Negative enlargement reverses position about its centre.
- When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
AB and BA always have the same components. This claim is false. Explain which definition or assumption it violates.
Find the magnitude of (4,3). · Trouvez la norme de (4,3).
Magnitude=√(4²+3²)=5.
AB and BA always have the same components. · AB et BA ont toujours les mêmes composantes.
The order of subtraction matters: BA=-AB. Proving parallelism needs a scalar-multiple relation; a sketch alone is insufficient. Negative enlargement reverses position about its centre. · L'ordre de la soustraction est important : BA=-AB. Prouver le parallélisme nécessite une relation de multiple scalaire ; un simple croquis est insuffisant. Une dilatation négative inverse la position par rapport à son centre.
Interpret a new situation
- Use vector components, scalar multiples and magnitudes for displacements and forces. This unit does not require the scalar product.
- A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Find the y-component of (4,1)+(1,3). · Trouver la composante y de (4,1)+(1,3).
Add the y-components: 1+3=4. · Additionner les composantes y : 1+3=4.
Match each part of a complete solution to its purpose. · Associer chaque partie d'une solution complète à son but.
An assumption justifies the model; a check tests the result; interpretation connects it to the question. · Une hypothèse justifie le modèle ; une vérification teste le résultat ; l'interprétation le relie à la question.
Use this in your course
- 7357 · A-level · J. Match the target tier and specification before assigning extensions.
- Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
The vector sum representing the combined displacement or force. Choose the relationship, show the method, check its assumptions and interpret the result.