题目

阅读下面短文，根据其内容写一篇60词左右的内容概要。The gene is often called the building block of life, because it is the smallest unit to carry information from one generation to another. Scientists working in the field of genetics are able to understand how one generation inherits important characteristics from the previous generation. But we are able to understand much more than merely why a particular family has a large number of red—haired children. We are also able to discover whether an individual is likely to live a long life, or suffer from particular diseases如图14所示，一质量不计的轻质弹簧的上端与盒子A连接在一起，盒子A放在倾角为θ=300的光滑固定斜面上,下端固定在斜面上.盒子内装一个光滑小球，盒子内腔为正方体，一直径略小于此正方形边长的金属圆球B恰好能放在盒内，已知弹簧劲度系数为k=100N/m，盒子A和金属圆球B质量均为1kg.，将A沿斜面向上提起，使弹簧从自然长度伸长10cm，从静止释放盒子A，A和B一起在斜面上做简谐振动，g取10m/s2，求：（1）盒子A的振幅.（2）金属圆球B的最大速度.（3）盒子运动到最低点和最高点时，盒子A对金属圆球B的作用力大小