Density, Hooke's law and stress-strainAQA A-Level Physics: Mind map

Exam questions on Density, Hooke's law and stress-strain

1. A solid rectangular block of metal measures 4.0 cm by 5.0 cm by 2.0 cm and has a mass of 108 g.
   A second block is made from the same metal and has the same outside dimensions, but it contains a hollow cavity. Its mass is 80 g. Calculate the volume of the cavity.2 marks
2. A student hangs masses from a helical steel spring. A load of 4.0 N produces an extension of 0.080 m. The spring obeys Hooke's law up to its elastic limit, which is reached at a load of 6.0 N.
   A load of 9.81 N is hung from the spring, which is greater than the elastic limit. Describe two ways in which the behaviour of the spring differs from its behaviour at loads below the limit.2 marks
3. A steel wire of length 2.50 m and diameter 0.50 mm hangs from a fixed support. A load of 80 N is hung from its lower end, and the wire extends by 3.0 mm. The wire is within the region where it obeys Hooke's law.
   Define tensile stress and tensile strain, and state the unit of tensile stress.3 marks