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几何知识,在物理解题中有很多应用,尤其是在力学和光学中,用的更多.请看以下几例: 例1 一电线杆在阳光照射下,产生的影子长5 米,一身高1.8米的人直立时产生的影子长1.2米,则电线杆的高度是多少? 分析本题运用光的直线传播规律,并借助于数学中的相似形的知识,可使解题过程变的简捷. 解如图1,AB为电线杆长,DE为人的身高,DE=1.8米,BC=5米,EC =1.2米,由图可知△ABC∽△DEC,
Geometry knowledge, there are many applications in the matter of understanding, especially in mechanics and optics, use more. Please see the following examples: Example 1 A pole in the sun, the shadow produced is 5 meters long, a tall When a 1.8 meter person stands upright, the length of the shadow produced is 1.2 meters. What is the height of the pole? Analyzing the rule of linear propagation of light, and using the knowledge of similar shapes in mathematics, the problem-solving process can be simplified. Solution as shown in Figure 1, AB is the pole length, DE is the height of the person, DE = 1.8 meters, BC = 5 meters, EC = 1.2 meters, from the figure we can see △ ABC ∽ △ DEC,