论文部分内容阅读
人们都说能力比知识更重要,而能力的重要方面是科学方法,如何学会灵活应用科学方法?这是人们很关注的话题。答案应该是:只能在应用的实践中培养。现看下面两例。问题:一杯中装有半杯水,水深5厘米,今放入一边长为2厘米的正方体小石块,水深变为6厘米,未溢出。若小石块的密度ρ石=2.5×103千克/米3,求小石块受到的浮力与石块对杯底的压力(g取10N/kg)。显然,石块与杯底是不紧密接触的,浮力大小可由阿基米德定律求得:
People say that ability is more important than knowledge, and the important aspect of competence is the scientific method. How to learn to apply scientific methods flexibly? This is a topic that people are very concerned about. The answer should be: Can only be cultivated in the application of the practice. Now see the following two examples. Question: One cup is filled with half a glass of water, with a water depth of 5 cm. Today, it is placed in a square cube with a length of 2 cm on one side, and the water depth is changed to 6 cm without overflowing. If the density of the small stones is ρ = 2.5 × 103 kg/m 3 , then the buoyancy of the small stones and the pressure of the stones on the bottom of the cup (g = 10 N/kg) are required. Obviously, the stones are not in close contact with the bottom of the cup. The size of the buoyancy can be obtained from Archimedes’ law: