Physics 9702 · AS & A Level · Elastic and plastic behaviour

Elastic and plastic behaviour — practice question

(a(i))[1]

Define what stress is.

(a(ii))[1]

Define strain.

(b)[1]

Explain the term elastic limit.

(c)[2]

Explain the term ultimate tensile stress.

(d(i))[2]

A ductile wire is pulled until it reaches breaking point. On Fig. 3.1, sketch how the stretching force $F$ varies with extension $x$.

(d(ii))[1]

On Fig. 3.2, sketch how $F$ varies with $x$ for a brittle material up to its breaking point.

(e(i))[2]

Explain the graph features in (d) that demonstrate the properties of ductile and brittle materials.

(e(ii)-1)[1]

The force $F$ is removed from the materials in (d) just before the breaking point is reached. Describe the change that follows in the extension for the ductile material.

(e(ii)-2)[1]

The force $F$ is removed from the materials in (d) just before the breaking point is reached. Describe the change that follows in the extension for the brittle material.

(e(ii).1)[1]

The force $F$ is removed from the materials in (d) just before the breaking point is reached. Describe the change that follows in the extension for the ductile material.

(e(ii).2)[1]

The force $F$ is removed from the materials in (d) just before the breaking point is reached. Describe the change that follows in the extension for the brittle material.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: stress $= \dfrac{\text{force}}{\text{cross-sectional area}}$

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