Asian Physics Olympiad · Year 2011

Problems

Problem 1A mass $m$ slides from rest down a frictionless incline of length $s$ and angle $\alpha$ . Find its acceleration, final speed, and travel time; gravity is $g$ . (a) State the assumptions and establish the governing equation for the requested quantity. (b) Solve it in terms of the given symbols, identifying the direction, sign, or physical nature of the result. (c) Check a simple limiting case and state when the model remains valid. Use SI units consistently, retain the symbols in the setup, and enforce all geometric constraints and initial conditions.Solutions: 1
Problem 2A resistor $R$ is connected to a constant voltage source $V$ . Find the current, heating power, and heat released during time $t$ . (a) State the assumptions and establish the governing equation for the requested quantity. (b) Solve it in terms of the given symbols, identifying the direction, sign, or physical nature of the result. (c) Check a simple limiting case and state when the model remains valid. Use SI units consistently, retain the symbols in the setup, and enforce all geometric constraints and initial conditions.Solutions: 1
Problem 3An atom of mass $M$ , initially at rest, absorbs a photon of wavelength $\lambda$ . Assuming $Mc^2\gg hc/\lambda$ , find its approximate recoil speed; $h$ is Planck’s constant and $c$ the speed of light. (a) State the assumptions and establish the governing equation for the requested quantity. (b) Solve it in terms of the given symbols, identifying the direction, sign, or physical nature of the result. (c) Check a simple limiting case and state when the model remains valid. Use SI units consistently, retain the symbols in the setup, and enforce all geometric constraints and initial conditions.Solutions: 1