Physics (AS & A Level) · Feb / March 2020 · Paper 12 · Question 19

A composite rod is made by attaching a glass-reinforced plastic rod and a nylon rod end to end, as shown. The rods have the same cross-sectional area and each rod is 1.00 m in length. The Young modulus Ep of the plastic is 40 GPa and the Young modulus En of the nylon is 2.0 GPa. The composite rod will break when its total extension reaches 3.0 mm. What is the greatest tensile stress that can be applied to the composite rod before it breaks?

1. A2.9 × 10^6 Pa
2. B5.7 × 10^6 Pa
3. C2.9 × 10^9 Pa
4. D5.7 × 10^9 Pa

As printed in the paper