*Learners should be able to demonstrate and apply their knowledge and understanding of:*

**2.1 Physical quantities and units**

**2.1.1 Physical quantities**

(a) physical quantities have a numerical value and a unit

(b) making estimates of physical quantities listed in this specification.

**2.1.2 S.I. units**

(a) Système Internationale (S.I.) base quantities and their units – mass (kg), length (m), time (s), current (A), temperature (K), amount of substance (mol)

(b) derived units of S.I. base units

(c) units listed in this specification

(d) checking the homogeneity of physical equations using S.I. base units

(e) prefixes and their symbols to indicate decimal submultiples or multiples of units – pico (p), nano (n), micro (μ), milli (m), centi (c), deci (d), kilo (k), mega (M), giga (G), tera (T)

(f) the conventions used for labelling graph axes and table columns.

**2.2 Making measurements and analysing data**

**2.2.1 Measurements and uncertainties**

(a) systematic errors (including zero errors) and random errors in measurements

(b) precision and accuracy

(c) absolute and percentage uncertainties when data are combined by addition, subtraction, multiplication, division and raising to powers

(d) graphical treatment of errors and uncertainties; line of best fit; worst line; absolute and percentage uncertainties; percentage difference.

**2.3 Nature of quantities**

**2.3.1 Scalars and vectors**

(a) scalar and vector quantities

(b) vector addition and subtraction

(c) vector triangle to determine the resultant of any two coplanar vectors

(d) resolving a vector into two perpendicular components; ; .