An engineer is selecting a material for a tension brace on a weather-monitoring balloon platform.
The brace has a volume of 300 cm3 and must have a mass of no more than 0.60 kg.
The maximum tensile stress on the brace will be 175 MPa. For safety, the tensile strength of the material must be at least twice the maximum tensile stress.
| Material | Density (g/cm3\mathrm{g/cm^3}g/cm3) | Tensile strength (MPa\mathrm{MPa}MPa) |
|---|---|---|
| Steel | 7.8 | 400 |
| Carbon-fibre composite | 1.6 | 600 |
| Poly(ethene) | 0.95 | 30 |
Explain which material the engineer should choose. Show your calculations.
136 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.