C.2 Algebra

Understand and use =, <, ≪, ≫, >, ∝, ≈ and Δ in physical relationships.

Use c.2.1—mathematical symbols to connect the rule to the data and decision in the question.

This matters because c.2.1—mathematical symbols determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply c.2.1—mathematical symbols to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: C.2.1—Mathematical symbols is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Change the subject of equations, including non-linear equations such as rearranging E = mc².

Use c.2.2—changing the subject of equations to connect the rule to the data and decision in the question.

This matters because c.2.2—changing the subject of equations determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply c.2.2—changing the subject of equations to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: use the formula and units given in the question, show the substitution and interpret the result; the calculation alone is not the conclusion.

Substitute numerical values into algebraic equations using appropriate units for physical quantities.

Use c.2.3—substitution into equations to connect the rule to the data and decision in the question.

This matters because c.2.3—substitution into equations determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply c.2.3—substitution into equations to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: use the formula and units given in the question, show the substitution and interpret the result; the calculation alone is not the conclusion.

Solve algebraic equations, including quadratic equations and kinematic equations for constant acceleration.

Use c.2.4—solving algebraic equations to connect the rule to the data and decision in the question.

This matters because c.2.4—solving algebraic equations determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply c.2.4—solving algebraic equations to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: use the formula and units given in the question, show the substitution and interpret the result; the calculation alone is not the conclusion.

Use logarithms for quantities spanning several orders of magnitude and interpret real-world logarithmic scales.

Use c.2.5—logarithmic quantities to connect the rule to the data and decision in the question.

This matters because c.2.5—logarithmic quantities determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply c.2.5—logarithmic quantities to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: C.2.5—Logarithmic quantities is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.