Skip to content
Oscar Song Tutoring

Edexcel A-level Maths revision notes

Quantities and units in mechanics

Section M6
Years 1 and 2
Years 1 and 2: this holds AS subject content and content the exam board adds beyond it for the full A-level.
1 specification point

Notes and three levels of exam-style practice for each registered specification point in this section.

Checked against Edexcel 9MA0 section M6

Checked against Edexcel 9MA0 section M6. Review basis: the qualification registry sourced from the Pearson Edexcel Level 3 Advanced GCE in Mathematics (9MA0) specification; registry verification recorded 11 July 2026.

How this checking works

In the exam: Formulae booklet provided · calculator allowed in every paper

Open the printable packRead the notes on one page
Year 1
Year 1: this point starts in the AS subject content, which is what most schools teach in Year 12. The full A-level adds in Year 2: Moment, as a derived quantity with its units.Year 2 adds: Moment, as a derived quantity with its units.

Understand and use fundamental quantities and units in the S.I. system: length, time, mass; understand and use derived quantities and units: velocity, acceleration, force, weight, moment.

Notes
Worked answers & exam appearances →
Evidence from your answers: none yet
Your confidence:

A self-report of how sure you feel. It does not measure mastery. Evidence from your answers reaches secure after the latest Tier 2/3 attempt is correct, with three correct distinct drills across at least two dates and two practice sources.

Explanation

  • The fundamental S.I. quantities are length in metres, time in seconds and mass in kilograms; velocity uses m s−1\text{m s}^{-1}, acceleration m s−2\text{m s}^{-2}, force and weight newtons, and moment N m\text{N m}.
  • Convert all measurements to consistent S.I. units before substituting, using for example 1 km h−1=518 m s−11\,\text{km h}^{-1}=\dfrac{5}{18}\,\text{m s}^{-1} and 1 tonne=1000 kg1\,\text{tonne}=1000\,\text{kg}.
  • Since F=maF=ma, 1 N=1 kg m s−21\,\text{N}=1\,\text{kg m s}^{-2}; multiplying a force by a perpendicular distance gives a moment in N m\text{N m}.
  • A common error is to confuse mass with weight: mass is measured in kilograms, whereas weight is a force measured in newtons; a moment is not measured in newtons alone.
Worked example

A resultant force gives a 750 kg750\,\text{kg} car an acceleration of 1.6 m s−21.6\,\text{m s}^{-2}. Find the force in newtons and write the newton in fundamental S.I. units.

  1. 1.Using F=maF=ma, F=750×1.6=1200 NF=750\times1.6=1200\,\text{N}.
  2. 2.Since mass has unit kg\text{kg} and acceleration has unit m s−2\text{m s}^{-2}, the fundamental-unit form is kg m s−2\text{kg m s}^{-2}.

Answer: 1200 N1200\,\text{N}; 1 N=1 kg m s−21\,\text{N}=1\,\text{kg m s}^{-2}

Common mistakes

  • Don't convert centimetres to metres by dividing by 1010 rather than by 100100.
  • Don't treat the newton as a fundamental unit rather than deriving it from mass times acceleration.

Exam tip

Carry units through the calculation and express derived force units as kilograms metres per second squared when requested.

Tier 1 · Easy

ORIGINAL

1.

Convert 90 km h−190\,\text{km h}^{-1} to metres per second.

(2)

(Total for Question 1 is 2 marks)

Tier 2 · Standard

ORIGINAL
Year 2 part
Moment of a force

1.

A student states that velocity is measured in m s−2\text{m s}^{-2}, acceleration in m s−1\text{m s}^{-1}, force in kg m s−2\text{kg m s}^{-2} and moment in kg m2s−2\text{kg m}^2\text{s}^{-2}. Identify the two incorrect statements and correct them.

(4)

(Total for Question 1 is 4 marks)

Tier 3 · Hard

ORIGINAL
Year 2 part
Moment of a force

1.

A vehicle of mass 1.81.8 tonnes increases its speed uniformly from 54 km h−154\,\text{km h}^{-1} to 90 km h−190\,\text{km h}^{-1} in 8.0 s8.0\,\text{s}. Find the resultant force. This force has a perpendicular distance of 0.65 m0.65\,\text{m} from a pivot; find its moment about the pivot.

(6)

(Total for Question 1 is 6 marks)

Your progress and exam materials

This section: Evidence from your answers: 0/1 secureYour confidence: 0 self-rated secureTracker status: 0/1 secure, 0 shaky, 1 unseen

Overall: Evidence from your answers: 0/89 secureYour confidence: 0 self-rated secureTracker status: 0/89 secure, 0 shaky, 89 unseen

Progress is saved on this device for guests and accounts right now; cross-device account sync is not live yet.

Answer conventions

Follow the wording on the question and its mark scheme. awrt means an appropriately rounded value is accepted; an exact answer must stay as a fraction, surd, logarithm or multiple of π when required, and a rounded decimal may be disallowed. Include requested units and forms. A cso tag protects that accuracy mark, while earlier method marks follow the question-specific dependencies.

See everything due today — your streak and what to revise next, kept on this device.

Want help turning these notes into marks?

Bring a tricky specification point or a recent answer, and we can work through the method and exam wording together.

Book a free intro call