(a(i))[2]
Compare the molecular motion in a liquid and in a solid.
(a(ii))[1]
Compare the molecular motion in a liquid and in a gas.
(b(i))[1]
A ductile material in the form of a wire is stretched up to its breaking point. On Fig. 4.1, sketch how the stretching force $F$ varies with extension $x$.
(b(ii))[1]
On Fig. 4.2, sketch how the stretching force $F$ varies with extension $x$ for a brittle material up to its breaking point.
(c)[2]
Describe one similarity and one difference between ductile and brittle materials.