Exam-style Questions: Deformation of Solids

  1. The images A and B show two different kinds of fracture.

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    State the two kinds of fracture, for each suggesting a material that fractures in this way.

    A shows .....................................fracture,

    a possible materials is ................................ .

    B shows .................................... fracture,

    a possible material is .................................. .

    (4 Marks)

  2. A metal wire is suspended from a fixed point. Increasing weights are added to the lower end of wire. The stress and strain in the wire are as follows.

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    a) On the axis below, plot the points and draw the graph of stress against strain.

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    (2 Marks)

    b) Use the graph (i) to calculate the Young modulus of the maetrial of the wire.

    Young modulus = .......................... Pa

    (3 Marks)

    (Marks available: 5)

Answer

Answer outline and marking scheme for question:

  1. A: ductile / plastic fracture AW

    e.g. metals / copper / plastics / pvc (all correct)

    B: brittle / clean fracture AWv

    e.g. glass / cermaic / named alloy / (cast) iron (all correct)

    (4 Marks)

  2. a) All points plotted correctly;

    Correct graph shown: straight section through origin and curve.

    (2 Marks)

    b) Use of point on straight line / gradient of straight line used;

    Correct data from graph;

    Young modulus between 1.2 x 1011 Pa and 1.3 x 1011 Pa

    (3 Marks)

    (Marks available: 5)