Quelpr
6 marksMechanical Properties of Materials

CAPE Physics Unit 1 · May/June 2022 · Paper 2 · Question 3(c)(v)

Stress-strain curves for spider and silkworm silk (Figure 5).

An insect flies into a spider’s web and becomes attached to a single thread, creating a tension of 580 μN. The thread extends by approximately 3% of its original length. Calculate the radius of a single thread of spider silk.

This question uses a figure or table from the paper — you'll see it when you practise.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 3(a)(i)Define the term 'stress', and state the unit in which it is measured.[3 marks]
  2. 3(a)(ii)Define the term 'strain', and state the unit in which it is measured.[2 marks]
  3. 3(b)(i)Describe the behaviour of the metal wire in EACH of the following segments of the graph: AB, BC, CD.[4 marks]
  4. 3(b)(ii)Explain what is meant by the 'elastic limit' of a wire.[2 marks]
  5. 3(b)(iii)If EACH major interval on the vertical axis of the graph in Figure 4 represents 150 MPa, determine the elastic limit of the wire.[1 mark]
  6. 3(b)(iv)The wire can be described as a ductile material. State TWO properties of ductile materials.[2 marks]
  7. 3(b)(v)In terms of the wire, what does the interval AD on the graph represent?[1 mark]
  8. 3(b)(vi)State how the energy per unit volume stored in the wire during the loading process can be determined from the graph.[1 mark]
  9. 3(c)(i)State what is meant by the term 'high tensile strength'.[1 mark]
  10. 3(c)(ii)Using the graph in Figure 5, explain how the properties of spider silk make it more suitable than silkworm silk for building webs to catch insects.[2 marks]
  11. 3(c)(iii)Using the graph in Figure 5, determine the MAXIMUM amount of energy that can be stored by silkworm silk before it fractures.[3 marks]
  12. 3(c)(iv)Using the graph in Figure 5, determine the Young’s modulus of spider silk for small stresses.[2 marks]

More practice: the rest of this paper · more Mechanical Properties of Materials questions · all CAPE Physics Unit 1 past papers