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6.2. Elastic and plastic behaviour
A subsection of Physics, 9702, through 6. Deformation of solids
Listing 10 of 75 questions
A solid cylinder is lifted out of oil by a wire attached to a motor. shows two different positions X and Y of the cylinder during the lifting process. wire cylinder at position X motor beam velocity 0.020 m s–1 surface of oil oil cylinder at position Y The motor is fixed to an overhead beam. The cylinder has cross-sectional area 0.018 m2, length 1.2 m and weight 560 N. The density of the oil is 940 kg m–3. Throughout the lifting process, the cylinder moves vertically upwards with a constant velocity of 0.020 m s–1. The viscous force of the oil acting on the cylinder is negligible. Calculate the density of the cylinder. density = kg m–3 For the cylinder at position X, show that the upthrust due to the oil is 200 N. Calculate, for the moving cylinder at position X, the tension in the wire, tension = N the power output of the motor. power = W The cylinder is raised with constant velocity from position X to position Y. State and explain the variation, if any, of the power output of the motor as the cylinder is raised. Numerical values are not required. The rate of energy output of the motor is less than the rate of increase of gravitational potential energy of the cylinder. Without calculation, explain this difference.
9702_s18_qp_22
THEORY
2018
Paper 2, Variant 2
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A cylindrical disc of mass 0.24 kg has a circular cross-sectional area A, as shown in . cross-sectional area A disc, mass 0.24 kg ground disc force X 8.9 N 30° constant speed 0.60 m s–1 The disc is on horizontal ground, as shown in . A force X of magnitude 8.9 N acts on the disc in a direction of 30° to the horizontal. The disc moves at a constant speed of 0.60 m s−1 along the ground. Determine the rate of doing work on the disc by the force X. rate of doing work = W The force X and the weight of the disc exert a combined pressure on the ground of 3500 Pa. Calculate the cross-sectional area A of the disc. A = m2 Newton’s third law describes how forces exist in pairs. One such pair of forces is the weight of the disc and another force Y. State: the direction of force Y the name of the body on which force Y acts.
9702_s19_qp_23
THEORY
2019
Paper 2, Variant 3
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State Hooke’s law. The variation of the applied force with the extension for a sample of a material is shown in . extension / mm force / N X The sample behaves elastically up to an extension of 80 mm and breaks at point X. On the line in , draw a cross (×) to show the limit of proportionality. Label this cross with the letter P. On the line in , draw a cross (×) to show the elastic limit. Label this cross with the letter E. The sample in has a cross-sectional area of 0.40 mm2 and an initial length of 3.2 m. For deformations within the limit of proportionality of the sample, determine: the spring constant of the sample spring constant = N m–1 the Young modulus of the material from which the sample is made. Young modulus = Pa Determine an estimate of the work done on the sample as it is extended from zero extension to its breaking point. Explain your reasoning. work done = J A second sample of the same material has a larger cross-sectional area than the original sample but the same initial length. The two samples are each deformed with the limit of proportionality. State and explain qualitatively how the spring constant of the second sample compares with that of the original sample.
9702_s24_qp_23
THEORY
2024
Paper 2, Variant 3
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Questions Discovered
75