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一、填空(每空1分,共28分) 1.电荷间相互作用的规律是:同种电荷互相____;异种电荷互相____。 2.物体由于地球____而受到的力叫做重力,它的方向总是____的。 3.改变物体的内能有____和____两种方式。 4.两力平衡的条件是:作用在同一物体上的两个力,必须____相等,____相反,并作用在同一直线上。 5.光在真空中的传播速度是____米/秒,在同一种物质中,光是沿____传播的。 6.照相机是利用____透镜能成____象的原理制成的。
First, fill in the blank (1 point for each, a total of 28 points) 1. The law of interaction between the charges is: the same kind of charge each other ____; heterogeneous charge mutual ____. 2. The force that an object receives because of the Earth’s ____ is called gravity, and its direction is always ____. 3. Change the internal energy of the object in two ways: ____ and ____. 4. The condition of two-force balance is that the two forces acting on the same object must be equal to ____, opposite to ____, and act on the same line. 5. The speed of light propagation in vacuum is ____m/s. In the same substance, light travels along ____. 6. The camera is made using the principle that ____ lenses can be made into ____ images.