City Guilds Model Questions Vol1 2018 Engineering Question 5

A cylindrical steel rod is to be tested for its tensile properties using a universal testing machine. The rod is nominally 300 mm long. Its diameter is measured at three points along its length and recorded as 12.02 mm, 11.98 mm and 12.00 mm. The rod is then loaded gradually until fracture. The following load‑extension data are obtained (the load is the reading on the machine, the extension is the increase in gauge length measured with a vernier caliper). After fracture the two pieces are laid end‑to‑end and the total length is measured as 340 mm. | Extension (mm) | Load (N) | |----------------|----------| | 0.3 | 22 500 | | 0.6 | 45 000 | | 0.9 | 65 000 | | 1.2 | 80 000 | | 1.5 | 90 000 | | 2.0 | 100 000 | | 2.5 | 105 000 | | 3.0 | 108 000 | Using this information, answer the following: