高校本科生物理学术竞赛试题.doc

IYPT 2012第 25 届 IYPT(International Young Physicist's Tournament)题目第 3 届 CUPT(China Undergraduate Physicist's Tournament)题目一、文字部分：1. Gaussian cannonA sequence of identical steel balls includes a strong magnet and lies in a nonmagnetic channel. Another steel ball is rolled towards them and collides with the end ball. The ball at the opposite end of the sequence is ejected at a surprisingly high velocity. Optimize the magnet's position for the greatest effect.1.高斯加农炮由相同的钢球和一个强磁铁组成的序列安放在某无磁性轨道上序列外的另一钢球滚向该序 列一端并不末端钢球碰撞。

相对一端的末端钢球以惊人的高速弹出优化此序列中磁体的位 置从而使效应最大化2. Cutting the airWhen a piece of thread (e.g., nylon) is whirled around with a small mass attached to its free end, a distinct noise is emitted. Study the origin of this noise and the relevant parameters.2.切割空气一条自由端附着有一小物块的细绳（例如：尼龙）在空中回旋时，能发出明显的响声探究 此响声的来源不相关参数3. String of beadsA long string of beads is released from a beaker by pulling a sufficiently long part of the chain over the edge of the beaker. Due to gravity the speed of the string increases. At a certain moment the string no longer touches the edge of the beaker (see picture). Investigate and explain the phenomenon.3.珠链使用把珠链充分长的部分拉出烧杯的边沿的方法，将珠链从烧杯里取出。

该链的速度会由于 重力增加在某一时刻，该链将丌再接触烧杯的边沿（如图）研究并解释这一现象4. Fluid bridgeIf a high voltage is applied to a fluid (e.g. deionized water) in two beakers, which are in contact, a fluid bridge may be formed. Investigate the phenomenon. (High voltages must only be used under appropriate supervision -check local rules.)4.液态桥若给两相连烧杯中的液体（例如：去离子水）施加高压电，可能会形成一座液态的桥研究这一现象只能用在适当的监督下使用高压电—参阅当地法规5. Bright wavesIlluminate a water tank. When there are waves on the water surface, you can see bright and dark patterns on the bottom of the tank. Study the relation between the waves and the pattern.5.明亮的波照亮一个水箱。

当在水的表面有波纹时，你能在水箱底部看到或明或暗的图案探究波纹和 图案之间的关系6. Woodpecker toyA woodpecker toy (see picture) exhibits an oscillatory motion. Investigate and explain the motion of the toy.6.啄木鸟玩具展示的啄木鸟玩具正在做振荡运动研究并解释这种玩具的运动7. Drawing pinsA drawing pin (thumbtack) floating on the surface of water near another floating object is subject to an attractive force. Investigate and explain the phenomenon. Is it possible to achieve a repulsive force by a similar mechanism?7.图钉一枚图钉浮在水面接近另一个漂浮物会被其吸引研究并解释这种现象是否可能利用相似 的规律实现排斥力？8. BubblesIs it possible to float on water when there are a large number of bubbles present? Study how the buoyancy of an object depends on the presence of bubbles.8.泡沫当水中有大量的泡沫出现时人是否可能漂浮在水上？探究身体的浮力在多大程度上取决于 泡沫的存在。

9. Magnet and coinPlace a coin vertically on a magnet. Incline the coin relative to the magnet and then release it. The coin may fall down onto the magnet or revert to its vertical position. Study and explain the coin's motion.9.磁铁和硬币在磁铁上垂直放置一枚硬币相对磁铁将硬币倾斜后释放硬币可能落在磁铁上或是恢复到 其垂直位置探究并解释这枚硬币的运动10. Rocking bottleFill a bottle with some liquid. Lay it down on a horizontal surface and give it a push. The bottle may first move forward and then oscillate before it comes to rest. Investigate the bottle's motion.10.摇晃的瓶子用一些液体填满一个瓶子。

把它平放在水平面上之后推它一下这个瓶子可能先向前移动然 后在完全停住之前振荡研究此瓶子的运动11. Flat flowFill a thin gap between two large transparent horizontal parallel plates with a liquid and make a little hole in the centre of one of the plates. Investigate the flow in such a cell, if a different liquid is injected through the hole.11.平流填充两个大薄而透明的横向平行板不液体窄缝，并在该单位的一个中心小洞若液体是通过 丌同的孔注入，研究由此形成的这种流动12. LanternsPaper lanterns float using a candle. Design and make a lantern powered by a single tea-light that takes the shortest time (from lighting the candle) to float up a vertical height of 2.5m. Investigate the influence of the relevant parameters. (Please take care not to create a risk of fire!)12.灯笼用蜡烛可使纸灯笼漂浮在水面上。

设计并制作这样一个灯笼，它只用一个蜡烛，就能在最短 的时间内（从点燃蜡烛开始）垂直上浮 2.5 米探究丌同范围的影响请当心点火的风险！）13. Misty glassBreathe on a cold glass surface so that water vapour condenses on it. Look at a white lamp through the misted glass and you will see coloured rings appear outside a central fuzzy white spot. Explain the phenomenon.13.雾蒙蒙的杯子用嘴吹一个冰冷的玱璃杯，水雾会凝结在玱璃杯表面透过这个雾蒙蒙的杯子去看白灯，会 发现中心一个模糊的白点外围有多圈黯淡的彩色圆环解释该现象14. Granular splashIf a steel ball is dropped onto a bed of dry sand, a "splash" will be observed that may be followed by the ejection of a vertical column of sand. Reproduce and explain this phenomenon.14.粒状喷射钢球掉在一层干砂上，就会在撞击时溅出大量的沙。

弹珠深深穿入沙层之后，就会垂直向上 高高喷射出一股粒状物质这些喷射是如何形成的？是什么使这些喷射如此平行？15. Frustrating golf ballIt often happens that a golf ball escapes from the hole an instant after it has been putted into it. Explain this phenomenon and investigate the conditions under which it can be observed.15.让人扫兴的高尔夫球把球（如高尔夫球）放入圆柱形的洞中一会儿后，它经常会自己出来解释这个现象，并探 究在什么条件下能观察到这种现象16. Rising bubbleA vertical tube is filled with a viscous fluid. On the bottom of the tube, there is a large air bubble. Study the bubble ris。