Stress, strain and the Young modulusEdexcel A-Level Physics: Mind map

Exam questions on Stress, strain and the Young modulus

1. A steel wire of length 2.50 m and cross-sectional area 0.50 mm² supports a load of 80 N. The Young modulus of steel is 2.0 × 10¹¹ Pa, and the wire obeys Hooke's law.
   Calculate the extension of the wire.2 marks
2. A student stretches a copper wire of diameter 0.60 mm and original length 1.80 m. A load of 50 N produces an extension of 1.4 mm.
   Explain why a long, thin wire is used in an experiment to measure the Young modulus of a metal.2 marks
3. A metal rod of original length 0.400 m and cross-sectional area 1.0 × 10⁻⁴ m² is tested in tension until it breaks. The stress–strain graph is a straight line through the origin up to a stress of 2.8 × 10⁸ Pa, where the strain is 1.4 × 10⁻³. The breaking stress of the rod is 4.5 × 10⁸ Pa.
   Calculate the Young modulus of the metal.3 marks