Physic Labs

International Physics Olympiad · Year 1985

Problems

  1. Problem 1A mass mm slides from rest without friction down an incline of angle alpha and vertical height hh. Find its speed at the bottom. Assume ideal objects and components, neglect unstated losses, and use SI units. (a) Derive the primary requested quantity from the appropriate law. (b) Analyze quantitatively how the result depends on the given parameters. (c) Check a physically meaningful limiting case and explain its meaning. State sign conventions, show reasoning, and check dimensions. (a) Calculate the requested quantity from the data. (b) Give the law or expression showing parameter dependence. (c) Examine a limit consistent with the model. The incline ends in a rough horizontal patch of length d and kinetic-friction coefficient mu, followed by a spring of stiffness k.Solutions: 1
  2. Problem 2A resistor RR is connected to an ideal battery of emf VV. Find the current and power. Assume ideal objects and components, neglect unstated losses, and use SI units. (a) Derive the primary requested quantity from the appropriate law. (b) Analyze quantitatively how the result depends on the given parameters. (c) Check a physically meaningful limiting case and explain its meaning. State sign conventions, show reasoning, and check dimensions. (a) Calculate the requested quantity from the data. (b) Give the law or expression showing parameter dependence. (c) Examine a limit consistent with the model. The source has emf E and internal resistance r; load R is in series, with terminal voltage U and current I.Solutions: 1
  3. Problem 3A converging thin lens has focal length ff; an object is at distance u>fu>f. Find image distance and magnification. Assume ideal objects and components, neglect unstated losses, and use SI units. (a) Derive the primary requested quantity from the appropriate law. (b) Analyze quantitatively how the result depends on the given parameters. (c) Check a physically meaningful limiting case and explain its meaning. State sign conventions, show reasoning, and check dimensions. (a) Calculate the requested quantity from the data. (b) Give the law or expression showing parameter dependence. (c) Examine a limit consistent with the model.Solutions: 1