国际青年物理学家竞赛IYPT2013试题(英文版).docVIP

IYPT 2013 in Taipei, Taiwan The IYPT 2013 will take place in Taipei, Taiwan. Further information will be announced in due time. Problems As decided by the IOC 2012-07-28, released 2012-08-01 PDF for printing There are more things in heaven and earth, Horatio,Than are dreamt of in your philosophy.Shakespeare 1. Invent yourself It is more difficult to bend a paper sheet, if it is folded “accordion style” or rolled into a tube. Using a single A4 sheet and a small amount of glue, if required, construct a bridge spanning a gap of 280 mm. Introduce parameters to describe the strength of your bridge, and optimise some or all of them. 2. Elastic space The dynamics and apparent interactions of massive balls rolling on a stretched horizontal membrane are often used to illustrate gravitation. Investigate the system further. Is it possible to define and measure the apparent “gravitational constant” in such a “world”? 3. Bouncing ball If you hold a Ping-Pong ball above the ground and release it, it bounces. The nature of the collision changes if the ball contains liquid. Investigate how the nature of the collision depends on the amount of liquid inside the ball and other relevant parameters. 4. Soliton A chain of similar pendula is mounted equidistantly along a horizontal axis, with adjacent pendula being connected with light strings. Each pendulum can rotate about the axis but can not move sideways (see figure). Investigate the propagation of a deflection along such a chain. What is the speed for a solitary wave, when each pendulum undergoes an entire 360o revolution? 5. Levitation A light ball (e.g. a Ping-Pong ball) can be supported on an upward airstream. The airstream can be tilted yet still support the ball. Investigate the effect and optimise the system to produce the maximum angle of tilt that results in a stable ball position. 6. Coloured plastic In bright light, a transparent plastic object (e.g. a blank CD case) can sometimes shine in various colours (s