Define the term strain.
A copper wire that is $4.0\,\text{m}$ long has a constant cross-sectional area of $4.5 \times 10^{-7}\,\text{m}^2$. A tensile force of $18\,\text{N}$ acts on the wire. The wire stretches by $1.4\,\text{mm}$, up to its limit of proportionality. Calculate the Young modulus of the wire.
A copper wire that is $4.0\,\text{m}$ long has a constant cross-sectional area of $4.5 \times 10^{-7}\,\text{m}^2$. A tensile force of $18\,\text{N}$ acts on the wire. The wire stretches by $1.4\,\text{mm}$, up to its limit of proportionality.
On Fig. 4.1, sketch a line to represent how stress changes with strain for the wire up to its limit of proportionality.
A second copper wire has the same length as the wire in (b), but its diameter is larger. Both wires are pulled by a tensile force of $18\,\text{N}$. Use a tick (✓) in each row to complete Table 4.1 and compare the stress and strain in the two wires.